Somatic Cloning Research Articles

Tracking the tumor evolution of patients with recurrence of ipsilateral breast tumor.

e12582 Background: After primary surgical resection, quite a proportion of breast cancer survivors would experience local recurrence within 5 years. Whether local recurrent tumors arise independently or from the primary tumors, which is critical for diagnosis and appropriate treatment, remains a clinical dilemma. Phylogenetic analysis between the primary and recurrent tumor provides a new strategy helpful for determining the origin of the local recurrent tumor. Methods: DNA was extracted from FFPE samples of the primary and recurrent tumors from 12 patients with recurrence of ipsilateral breast tumor. Phylogenetic analysis between the primary and recurrent tumors in the same individual was performed based on whole exome sequencing. PyClone and SciClone were employed to detect subclones. Results: The median time to recurrence of the 12 patients was 15 months (9 to 52 months). 9 (75%) of the 12 patients recurred within 2 years. Each patient had one shared somatic mutation clone between the primary and recurrent tumor, with shared somatic mutation number ranging from 5 to 59. This observation suggests that the recurrent tumor maybe originate from the primary tumor. Conclusions: The shared somatic mutation clone indicates the primary and recurrent tumor could be of the same origin and the recurrent tumor was metastasis from primary lesion. This may provide some information to help selecting the most appropriate treatment for patients.

Development of a cost-effective single nucleotide polymorphism genotyping array for management of greater yam germplasm collections.

Using genome‐wide single nucleotide polymorphism (SNP) discovery in greater yam (Discorea alata L.), 4,593 good quality SNPs were identified in 40 accessions. One hundred ninety six of these SNPs were selected to represent the overall dataset and used to design a competitive allele specific PCR array (KASPar). This array was validated on 141 accessions from the Tropical Plants Biological Resources Centre (CRB‐PT) and CIRAD collections that encompass worldwide D. alata diversity. Overall, 129 SNPs were successfully converted as cost‐effective genotyping tools. The results showed that the ploidy levels of accessions could be accurately estimated using this array. The rate of redundant accessions within the collections was high in agreement with the low genetic diversity of D. alata and its diversification by somatic clone selection. The overall diversity resulting from these 129 polymorphic SNPs was consistent with the findings of previously published studies. This KASPar array will be useful in collection management, ploidy level inference, while complementing accurate agro‐morphological descriptions.

Determining Influence of Culture Media and Dose-Dependent Supplementation with Basic Fibroblast Growth Factor on the Ex Vivo Proliferative Activity of Domestic Cat Dermal Fibroblasts in Terms of Their Suitability for Cell Banking and Somatic Cell Cloning of Felids

Abstract Dermal fibroblasts are commonly used as donors of genetic material for somatic cell nuclear transfer in mammals. Basic fibroblast growth factor (bFGF) is a cytokine that regulates proliferation and differentiation of different cell types. The study was aimed at optimizing the cell culture protocol for cat dermal fibroblasts by assessing the influence of culture media and different doses of bFGF on proliferation of fibroblasts and their viability in terms of cell banking and somatic cloning of felids. In Experiment I, skin biopsies of domestic cats were cultured in DMEM (D) and/or DMEM/F12 (F), both supplemented with 5 ng bFGF/ml (D-5, F-5, respectively). After the primary culture reached ~80% of confluency, the cells were passaged (3–4 times) and cultured in media with (D-5, F-5) or without (D-0, F-0) bFGF. To determine the optimal doses of bFGF, in Experiment II, secondary fibroblasts were cultured in DMEM with 0 (D-0), 2.5 (D-2.5), 5 (D-5) or 10 (D-10) ng bFGF/ml. The results showed that in D-5 the cells proliferated faster than in D-0, F-5 and F-0. Due to their poor proliferation, passages IV were not performed for cells cultured in F-0. In experiment II, a dose-dependent effect of bFGF on proliferation of cat dermal fibroblasts was found. In D-5 and D-10, the cells exhibited higher (P<0.05) proliferation compared with D-0. In D-2.5 the cells showed a tendency to proliferate slower than in D-5 and D-10 and at the same faster than in D-0. In conclusion. DMEM supplemented with bFGF provides better proliferation of domestic cat dermal fibroblasts culture than DMEM/F12. Supplementation of culture medium with bFGF has a beneficial effect on cat dermal fibroblast proliferation and could be recommended for addition to culture media.

Effects of serum starvation and ionomycin activation on the development of somatic cell nuclear transfer embryos in sheep

Synchronization of donor cells and activation of the reconstructed oocytes are important factors affecting the success rate in somatic cell cloning. In this study, it was aimed to investigate the effects of serum starvation in donor cell synchronization and ionomycin treatment in the activation of reconstructed oocytes after somatic cell nuclear transfer in Kivircik sheep. Cumulus cells were obtained from a slaughtered sheep ovaries and used as donor cells after serum starvation for 4 days (0.5% FCS; SS) or without serum starvation (10% FCS; S). After reconstruction, oocytes were activated by ionomycin for 5 min plus 6-dimethylaminopurine for 3 h (I+) or only with 6-dimethylaminopurine for 3 h (I-). All cleaved embryos (n= 44) at the second day of in vitro culture were transferred into synchronized recipient ewes (n= 10). Cleavage rates of the embryos were 37.3, 44.1, 34.6 and 44.7% in SS/I+, S/I+, SS/I- and S/Igroups, respectively. Recipient ewes had serum progesterone levels >1 ng/ml at 18 th day were 33.3, 50.0, 50.0 and 100.0%, respectively. Only one pregnancy in the S/I- group continued after 40 days however the cloned lamb (7.1%, regarding to embryos transferred) died 10 days before term due to a maternal problem (uterine torsion). The results of this study reveal that somatic cell synchronization by serum starvation and ionomycin treatment for the activation of oocytes can be omitted for the success of somatic cell nuclear transfer in sheep

Effects of fusion-activation interval and embryo aggregation on in vitro and in vivo development of bovine cloned embryos

Nuclear reprogramming in somatic cell cloning is one of the key factors for proper development, with variations in the protocol appearing to improve cloning efficiency. This study aimed to determine the effects of two fusion-activation intervals and the aggregation of bovine cloned embryos on subsequent in vitro and in vivo development. Zygotes produced by handmade cloning were exposed to two fusion-activation intervals (2 h or 4 h), and then cultured in microwells either individually (1 × 100%) or after aggregation of two structures (2 × 100%). Zona-intact oocytes and zona-free oocytes and hemi-oocytes were used as parthenote controls under the same fusion-activation intervals. Day-7 cloned blastocysts were transferred to synchronous recipients. Cleavage (Day 2), blastocyst (Day 7) and pregnancy (Day 30) rates were compared by the χ2 test (P < .05). Extending fusion-activation interval from 2 to 4 h reduced cleavage (91.0 vs. 74.4%) but not blastocyst (34.8 vs. 42.0%) rates. On a microwell basis, cloned embryo aggregation (2 × 100%) increased cleavage (91.5% vs. 74.4%) and blastocyst (46.0% vs. 31.3%) rates compared to controls (1 × 100%), but did not improve the overall embryo production efficiency on Day 7 (23.0% vs. 31.3%), on a per reconstructed embryo basis, respectively. Treatments had no effects on in vitro developmental kinetics, embryo quality, and in vivo development. In summary, the fusion-activation interval and/or the aggregation of cloned bovine embryos did not affect cloning efficiency based on the in vitro development to the blastocyst stage and on pregnancy outcome.

37 Viability of sheep skin fibroblasts after vitrification

Both tissue and cell cryopreservation can be applied for biodiversity conservation. The proper preservation of tissues and cells from a wide range of animals of different species is of paramount importance because these cell samples could be used to reintroduce lost genes back into the breeding pool by somatic cell cloning. The aim of this work was to investigate the effect of vitrification on viability of vitrified sheep fibroblasts for conservation of biodiversity so that it might be used in the future to provide nuclear donors. Skin samples collected from 10 adult sheep were cut into small pieces (1×1mm), placed into culture Petri dishes containing DMEM supplemented with 20% (vol/vol) fetal bovine serum, and covered with coverslips followed by incubation at 5% CO2, 95% RH, and 37°C. During culture, fibroblasts left skin samples and proliferated. Culture medium was changed every 4 days. After 21 to 22 days of incubation, a fibroblast monolayer was observed, culture medium was removed, and cells were incubated for 7 to 10min in the presence of Dulbecco’s PBS+0.25% trypsin. Dissociated fibroblasts were washed with DMEM by centrifugation at 300×g for 10min. For vitrification, fibroblast samples were then diluted at a concentration of 2×106cellsmL−1 in DMEM+ 20% ethylene glycol, 20% dimethylsulfoxide, and 0.5molL−1 of sucrose. The fibroblasts were then exposed to 50 and 100% vitrification solution (VS) at 37°C for 5min and 30s, respectively. Fibroblasts after saturation in VS were transferred and placed into 0.25-mL plastic straws. Straws were sealed with modelling clay and plunged into LN. Viability of frozen-thawed fibroblast samples was detected using the Trypan Blue staining method (frozen-thawed: 53.0±2.6%; control (fresh): 98.5±1.2%). The values obtained are expressed as mean±standard error of the mean. Statistical analysis was done using Student’s t-test. Results indicated that there was a significant difference in viability between fresh and cryopreserved fibroblasts. Importantly, our data suggest that the use of vitrification reduced the toxic elements contained in the cryopreservation solution while maintaining a similar ability to produce viable fibroblasts after cryopreservation. Although further work on the viability of sheep skin fibroblast with the vitrification method is needed, these data suggest that with vitrification a faster cooling rate and high level of cryoprotectants are able to minimize ice crystal formation and should be further evaluated as a routine mechanism for cryopreserving sheep fibroblasts.

Towards Improved Decision-Making Based on Genomics in Bone Marrow Failure

Inherited and acquired bone marrow failure syndromes (BMF) may be difficult to distinguish due to heterogeneity and overlap of clinical phenotypes. Genomic screening has been increasingly used to identify mutations in BMF-related genes that are known to be etiologic in inherited BMF. However, genomic testing is expensive, results may not return for several seeks, and findings can be difficult to interpret as some reported variants are of unclear clinical significance. To guide the decision-making for genetic testing and results interpretation, we aimed to identify clinical and molecular parameters associated with a higher probability of patients having an inherited disease. We screened 323 BMF patients from two independent cohorts for germline mutations in BMF-related genes using a targeted next-generation sequencing (NGS) assay, and correlated the results with patients' prior diagnosis, family history, telomere length (TL), karyotype, and the presence of a paroxysmal nocturnal hemoglobinuria (PNH) clones.Patients were followed at the Hematology Branch of NHLBI (NHLBI, n=179) and the Ribeirão Preto Medical School, University of São Paulo (USP, n=144). Diagnoses included were severe (SAA) and moderate aplastic anemia (MAA), isolated cytopenias, myelodysplastic syndrome (MDS), hypocellular MDS (HypoMDS), dyskeratosis congenita (DC), and Diamond-Blackfan anemia (DBA). Patients were classified as suspected to have inherited BMF (phenotype suggestive for constitutional disease, short or very short telomeres, family history of hematologic, pulmonary, or liver disease, and idiopathic cytopenias), or acquired BMF (normal TL and no signs of constitutional disease) (Figure 1A). Pathogenicity of novel and rare variants was assessed using the ACMG criteria.We identified a pathogenic (or likely pathogenic) germline variant in 21 (18%) and 44 (47%) inherited BMF patients from NHLBI and USP cohorts, respectively (Figure 1B). Altogether, mutated genes were associated with telomeropathies (mostly DC and MAA), congenital cytopenias, DBA, cryptic Fanconi anemia, and myeloid malignancies (Figure 1C). In both cohorts, inherited BMF patients with DC, DBA, MAA, and isolated cytopenias were more likely to have a pathogenic variant. BMF patients suspected to have an acquired disease were rarely found with a pathogenic variant; one patient from each cohort (NHLBI, 1.5% and USP, 2%), carried the R166A RUNX1 and A202T TERT variants, respectively. Overall, patients with SAA were highly unlikely to have a pathogenic variant, regardless of the clinical suspicion for constitutional disease (Figure 1B). The presence of PNH clone and chromosomal abnormalities were poorly associated with variants' pathogenicity; only one patient from the USP cohort had a PNH clone of 6% and the pathogenic TERT D718E variant, and three patients had an abnormal karyotype (indicated by asterisks in Figure 3C). In both cohorts, we additionally screened 101 acquired BMF and 140 inherited BMF patients for somatic clones in myeloid-driver genes. These results recapitulated the clonal landscape previously observed in AA by our group; the frequency of variants in ASXL1, DNMT3A, TET2, and JAK2, but not in BCOR and BCORL1, increased with aging. In the current study, TP53, RUNX1, and Ras genes were more frequently mutated in the patients suspected to have inherited BMF (Fisher's exact test, 14% vs. 4.4%; p<0.005) whereas BCOR and BCORL1 were more commonly abnormal in patients suspected to have acquired BMF (18% vs. 3.1%; p<0.005). Somatic mutations were particularly present in 5/21 DC patients (23%, median age, 11 years) but not in DBA (1 out of 11; median age, 3) and isolated cytopenias (median age, 6).In summary, inherited BMF patients were more likely to have a pathogenic variant compared to acquired BMF (18% vs. 1.5%, p<0.001). Inherited BMF patients with MAA and isolated cytopenias without PNH clones and a normal karyotype had increased risk of having constitutional disease. Systematic analysis of clinical and genomic data may be helpful to assist physicians in identifying patients who should be first screened for inherited BMF based on the probability of finding a pathogenic germline variant. [Display omitted] DisclosuresDunbar:National Institute of Health: Research Funding. Young:CRADA with Novartis: Research Funding; GlaxoSmithKline: Research Funding; National Institute of Health: Research Funding.

Efficient immortalization of cells derived from critically endangered Tsushima leopard cat (Prionailurus bengalensis euptilurus) with expression of mutant CDK4, Cyclin D1, and telomerase reverse transcriptase

Tsushima leopard cat is the subspecies of Amur cats, and it is classified as the most highest class of critically endangered animals. Although the protection activity is highly recognized, the number of animals is decreasing due to the human activity and invasion of domestic cats and infectious disease. In this study, we succeeded primary culture of normal fibroblasts derived from the Tsushima leopard cat (Prionailurus bengalensis euptilurus). Furthermore, we introduced the human derived mutant Cyclin Dependent Kinase 4, Cyclin D1, and telomere reverse transcriptase. We showed that the expression of these three genes efficiently immortalized cells derived from Tsushima leopard cat. Furthermore, we showed that the chromosome pattern of the established cells is identical with the original one. These data indicate that our method of immortalization is useful to establish cell lines from critically endangered cats, which potentially contributes to the re-generation of critically endangered animals from cultured cell with reproductive technique, such as somatic cloning.

Molecular and Cell Biological Considerations in the Initiation and Development of Sporadic Non-Hereditary Solid Cancers

This paper reviews the state of cancer research in the post-mutation era. It presents cancer as a highly complex disease viewed differently by scientists from various research fields. Histopathologists considered cancer as a disease of cell differentiation, cancer cell biologists overestimated the causal role of accumulated DNA mutations. More recently molecular biologists have focused on driver genes and driver mutations, regulatory gene networks and deregulation of the genomic balance between unicellular and multicellular gene sets (UG/MG balance). From a developmental biological standpoint, there is a clear analogy between the reproductive life cycles of cancer and protists. The key player of both analogous life cycles is the polyploid cyst, the atavistic cyst-like structure aCLS (PGCC). In the analogy to protists, we assume that the first aCLS initiating cancer originates from a mitoticly blocked cell (cell of origin of cancer, protoprecursor) that escapes death entering an atavistic reproductive process of polyploidisation and depolyploidisation; it forms the atavistic cyst-like structure aCLS and numerous daughter cells (microcells). The microcell progeny develops a multi-lined cell lineage containing stem cells as well as somatic and reproductive cells and clones. Subsequent aCLSs are formed sequentially by committed daughter cells or occasionally by stressed somatic cells. Accordingly, cancer initiation occurs by genomic changes leading to the amitotic cell state and reactivation of an atavistic life cycle. In humans, atavistic life cycles and hyperpolyploidisation (n &gt;16) are mostly repressed by stable gene regulatory networks – but not in cancer. The permanent UG/MG gene conflict and robust ancient surveillance mechanisms trigger a cascade of molecular lesions leading to genomic heterogeneity and aberrant cancer cell states.

Can Reprogramming of Overall Epigenetic Memory and Specific Parental Genomic Imprinting Memory within Donor Cell-Inherited Nuclear Genome be a Major Hindrance for the Somatic Cell Cloning of Mammals? – A Review

Abstract Successful cloning of animals by somatic cell nuclear transfer (SCNT) requires epigenetic transcriptional reprogramming of the differentiated state of the donor cell nucleus to a totipotent embryonic ground state. It means that the donor nuclei must cease its own program of gene expression and restore a particular program of the embryonic genome expression regulation that is necessary for normal development. Transcriptional activity of somatic cell-derived nuclear genome during embryo pre- and postimplantation development as well as foetogenesis is correlated with the frequencies for spatial remodeling of chromatin architecture and reprogramming of cellular epigenetic memory. This former and this latter process include such covalent modifications as demethylation/re-methylation of DNA cytosine residues and acetylation/deacetylation as well as demethylation/re-methylation of lysine residues of nucleosomal core-derived histones H3 and H4. The main cause of low SCNT efficiency in mammals turns out to be an incomplete reprogramming of transcriptional activity for donor cell-descended genes. It has been ascertained that somatic cell nuclei should undergo the wide DNA cytosine residue demethylation changes throughout the early development of cloned embryos to reset their own overall epigenetic and parental genomic imprinting memories that have been established by re-methylation of the nuclear donor cell-inherited genome during specific pathways of somatic and germ cell lineage differentiation. A more extensive understanding of the molecular mechanisms and recognition of determinants for epigenetic transcriptional reprogrammability of somatic cell nuclear genome will be helpful to solve the problems resulting from unsatisfactory SCNT effectiveness and open new possibilities for common application of this technology in transgenic research focused on human biomedicine.

Efficient Knock-in of a Point Mutation in Porcine Fibroblasts Using the CRISPR/Cas9-GMNN Fusion Gene.

During CRISPR/Cas9 mediated genome editing, site-specific double strand breaks are introduced and repaired either unspecific by non-homologous end joining (NHEJ) or sequence dependent by homology directed repair (HDR). Whereas NHEJ-based generation of gene knock-out is widely performed, the HDR-based knock-in of specific mutations remains a bottleneck. Especially in primary cell lines that are essential for the generation of cell culture and animal models of inherited human diseases, knock-in efficacy is insufficient and needs significant improvement. Here, we tested two different approaches to increase the knock-in frequency of a specific point mutation into the MYH7-gene in porcine fetal fibroblasts. We added a small molecule inhibitor of NHEJ, SCR7 (5,6-bis((E)-benzylideneamino)-2-mercaptopyrimidin-4-ol), during genome editing and screened cell cultures for the point mutation. However, this approach did not yield increased knock-in rates. In an alternative approach, we fused humanized Cas9 (hCas9) to the N-terminal peptide of the Geminin gene (GMNN). The fusion protein is degraded in NHEJ-dominated cell cycle phases, which should increase HDR-rates. Using hCas9-GMNN and point mutation-specific real time PCR screening, we found a two-fold increase in genome edited cell cultures. This increase of HDR by hCas9-GMNN provides a promising way to enrich specific knock-in in porcine fibroblast cultures for somatic cloning approaches.

Fixation and Spread of Somatic Mutations in Adult Human Colonic Epithelium

SummaryWe investigated the means and timing by which mutations become fixed in the human colonic epithelium by visualizing somatic clones and mathematical inference. Fixation requires two sequential steps. First, one of approximately seven active stem cells residing within each colonic crypt has to be mutated. Second, the mutated stem cell has to replace neighbors to populate the entire crypt in a process that takes several years. Subsequent clonal expansion due to crypt fission is infrequent for neutral mutations (around 0.7% of all crypts undergo fission in a single year). Pro-oncogenic mutations subvert both stem cell replacement to accelerate fixation and clonal expansion by crypt fission to achieve high mutant allele frequencies with age. The benchmarking of these behaviors allows the advantage associated with different gene-specific mutations to be compared irrespective of the cellular mechanisms by which they are conferred.

Somatic clones heterozygous for recessive disease alleles of BMPR1A exhibit unexpected phenotypes in Drosophila.

The majority of mutations studied in animal models are designated as recessive based on the absence of visible phenotypes in germline heterozygotes. Accordingly, genetic studies primarily rely on homozygous loss-of-function to determine gene requirements, and a conceptually-related 'two-hit model' remains the central paradigm in cancer genetics. Here we investigate pathogenesis due to somatic mutation in epithelial tissues, a process that predominantly generates heterozygous cell clones. To study somatic mutation in Drosophila, we generated inducible alleles that mimic human Juvenile polyposis-associated BMPR1A mutations. Unexpectedly, four of these mutations had no phenotype in heterozygous carriers but exhibited clear tissue-level effects when present in somatic clones of heterozygous cells. We conclude that these alleles are indeed recessive when present in the germline, but nevertheless deleterious when present in heterozygous clones. This unforeseen effect, deleterious heteromosaicism, suggests a 'one-hit' mechanism for disease initiation that may explain some instances of pathogenesis associated with spontaneous mutation.

Drosophila globin1 is required for maintenance of the integrity of F-actin based cytoskeleton during development

Hemoglobins (Hbs) are evolutionarily conserved small globular proteins with characteristic 3-over-3 α-helical sandwich structure that is typically known as “globin fold”. Hbs have been found to be involved in diverse biological functions and the characteristic property of oxygen transportation is relatively a recent adaptation. Drosophila genome possesses three globin genes (glob1, glob2, and glob3) and it was previously reported that adequate expression of glob1 is required for various aspects of development, and also to regulate the cellular level of reactive oxygen species (ROS). The present study illustrates the explicit role of glob1 gene in Drosophila development. We demonstrate a dynamic expression pattern of glob1 in larval tissues which largely concentrate around F-actin rich structures and also co-precipitate. Reduced expression of glob1 leads to developmental abnormalities which appeared to be largely mediated by inappropriately formed F-actin based cytoskeletal structures. Our subsequent analysis in FLP/FRT mediated somatic clones establishes specific role of Drosophila glob1 in maintenance of the integrity of F-actin based cytoskeleton during development. For the first time, we report interaction between Glob1 and actin, and propose a novel role of glob1 in maintenance of F-actin based cytoskeleton in Drosophila.

Explant origin and culture media factors drive the somatic embryogenesis response in Acrocomia aculeata (Jacq.) Lodd. ex Mart., an emerging oil crop in the tropics

The explant origin and the factors in the culture medium are responsible for the response to somatic embryogenesis in most plant species, including palms. Acrocomia aculeata is a neotropical palm currently undergoing domestication due to its sustainability and profitability as an alternative oil crop. The attainment of productive cultivars of this palm may be speed up by somatic embryogenesis. Thus, this study sought to refine an existing somatic embryogenesis cloning protocol for A. aculeata and to investigate the possible genetic influence on the in vitro propagation response, using zygotic embryos from 19 matrices or open-pollinated families. The embryos were inoculated in modified induction media. The following characteristics were evaluated in this phase: swollen embryos, percentage of zygotic embryos that formed callus, embryogenic calli and oxidation. Afterwards the resulting pro embryogenic masses were subsequently cultivated in modified multiplication, maturation and gemination media. In those phases the open-pollinated families’ response was measured by the growth of their embryogenic mass and the quantity of regenerated and germinated somatic embryos. The refined micropropagation protocol was successful in establishing embryogenic lines and maintaining their cyclic multiplication for a long period; all without the loss of their potential to maturate and regenerate somatic embryos. In general, the multiplication of pro embryogenic masses was effective even in the lowest dose of Picloram (18 μM). The addition of activated charcoal in the medium favored the maturation of somatic embryos. Plantlets regeneration, although defective in some lineages, was promoted by GA3 (0.55 μM). The zygotic embryos’ responsiveness to somatic embryogenesis varied according to their matrices, indicating that if micropropagation is to be used as a mass propagation technique for the species, the explant́s genotype must be considered.

Intrinsic and extrinsic molecular determinants or modulators for epigenetic remodeling and reprogramming of somatic cell-derived genome in mammalian nuclear-transferred oocytes and resultant embryos

The efficiency of somatic cell cloning in mammals remains disappointingly low. Incomplete and aberrant reprogramming of epigenetic memory of somatic cell nuclei in preimplantation nuclear- transferred (NT) embryos is one of the most important factors that limit the cloning effectiveness. The extent of epigenetic genome-wide alterations, involving histone or DNA methylation and histone deacetylation, that are mediated by histone-lysine methyltransferases (HMTs) or DNA methyltransferases (DNMTs) and histone deacetylases (HDACs) can be modulated/reversed via exogenous inhibitors of these enzymes throughout in vitro culture of nuclear donor cells, nuclear recipient oocytes and/or cloned embryos. The use of the artificial modifiers of epigenomically-conditioned gene expression leads to inhibition of both chromatin condensation and transcriptional silencing the genomic DNA of somatic cells that provide a source of nuclear donors for reconstruction of enucleated oocytes and generation of cloned embryos. The onset of chromatin decondensation and gene transcriptional activity is evoked both through specific/selective inactivating HMTs by BIX-01294 and through non-specific/non-selective blocking the activity of either DNMTs by 5-aza-2'-deoxycytidine, zebularine, S-adenosylhomocysteine or HDACs by trichostatin A, valproic acid, scriptaid, oxamflatin, sodium butyrate, m-carboxycinnamic acid bishydroxamide, panobinostat, abexinostat, quisinostat, dacinostat, belinostat and psammaplin A. Epigenomic modulation of nuclear donor cells, nuclear recipient cells and/or cloned embryos may facilitate and accelerate the reprogrammability for gene expression of donor cell nuclei that have been transplanted into a host ooplasm and subsequently underwent dedifferentiating and re-establishing the epigenetically dependent status of their transcriptional activity during pre- and postimplantation development of NT embryos. Nevertheless, a comprehensive additional work is necessary to determine whether failures in the early-stage reprogramming of somatic cell-inherited genome are magnified downstream in development of cloned conceptuses and neonates.

Generation of Cashmere Goats Carrying an EDAR Gene Mutant Using CRISPR-Cas9-Mediated Genome Editing.

In recent years, while the use of the clustered regularly interspaced short palindromic repeat (CRISPR)-CRISPR-associated protein 9 (Cas9) (CRISPR-Cas9) system for targeted genome editing has become a research hotspot, it has, to date, not proved adequate for genome editing in large mammals, such as goats. In this study, two opposite single-guide RNAs (sgRNAs) were designed for complete EDAR gene targeting in Cashmere goats, and co-transfected with a plasmid encoding Cas9 into goat fibroblasts. Among the 89 cell lines obtained through the cultivation of clonal cell lines, 62 were positive for EDAR gene targeting. Nine types of mutations were identified by sequencing analysis, and the mutation efficiency was 69.7%. Using one of these cell lines, EDAR gene-targeted Cashmere goat embryos were prepared by somatic cell cloning. Developed embryos were transferred to 79 Cashmere goat recipients, and, after a gestation period of five months six male EDAR gene-targeted Cashmere goats were born. Although only two of these goats survived, they had abnormal primary hair follicles and no hair on the top of their heads, which are the distinctive features of the EDAR gene-targeted Cashmere goats. Thus, this study provides a valuable animal model for future studies on EDAR gene-related phenotypes and hair follicle growth and development and shows that the CRISPR-Cas9 system can be used to edit genes in large mammals.

First attempt on somatic cell cryopreservation of critically endangered Camelus bactrianus of India

The double-humped camel (Camelus bactrianus) of India is critically endangered since the population is around two hundred only. Immediate measures are required for its conservation so as to prevent loss of this precious germplasm forever. This is the first report on development of ear marginal tissue fibroblast cell line from Bactrian camels using primary explant technique followed by cryopreservation. The cells showed typical fusiform morphology with centrally located oval nuclei with radiating, flame like or whirlpool like migrating patterns. Four different culture media MEM, DMEM-Hi glucose, DMEM/Ham's F-12 and fibroblast specific media (HiFibroXL™) were tested with respect to the potential to support growth of camel fibroblasts. Fibroblast specific media was selected for the primary culture. Maximum cell multiplication during secondary culture was supported by the DMEM/Ham's F-12 as total cell count with same seeding (80,000 cells) and under similar culture conditions was 6,75,000, 3,05,000, 13,90,000 and 10,05,000cells/mL for MEM, DMEM-Hi glucose, DMEM/Ham's F-12 and fibroblast specific media (HiFibroXL™), respectively. Cells followed a typical sigmoid growth curve with population doubling time of 26.13h. Epithelial and fibroblast cell initially grew together. However, fibroblast cells outgrew their epithelial counterparts in subsequent passages. Reverse transcriptase PCR was performed for individual samples at different passages by designing primers specific to Cytokeratin19 (CK19) and Osteopontin (OPN). Osteocytes were absent from the very beginning whereas, epithelial cells were eliminated after the first passage. Thus, the cells were cryopreserved from 4th to 6th passages. Chromosome karyotyping showed normal diploid (2n=74) number and the cells were free from microbial contaminations. Cells had more than 90% viability in the culture after one month of cryopreservation. These cells were morphologically indistinguishable from the cell stocks prior to freezing. Thus, genetic resource of Bactrian camel has been preserved at cellular level. The repository can also serves as a valuable resource for genome, post genome and somatic cell cloning research.

Selector genes display tumor cooperation and inhibition in Drosophila epithelium in a developmental context-dependent manner.

ABSTRACTDuring animal development, selector genes determine identities of body segments and those of individual organs. Selector genes are also misexpressed in cancers, although their contributions to tumor progression per se remain poorly understood. Using a model of cooperative tumorigenesis, we show that gain of selector genes results in tumor cooperation, but in only select developmental domains of the wing, haltere and eye-antennal imaginal discs of Drosophila larva. Thus, the field selector, Eyeless (Ey), and the segment selector, Ultrabithorax (Ubx), readily cooperate to bring about neoplastic transformation of cells displaying somatic loss of the tumor suppressor, Lgl, but in only those developmental domains that express the homeo-box protein, Homothorax (Hth), and/or the Zinc-finger protein, Teashirt (Tsh). In non-Hth/Tsh-expressing domains of these imaginal discs, however, gain of Ey in lgl− somatic clones induces neoplastic transformation in the distal wing disc and haltere, but not in the eye imaginal disc. Likewise, gain of Ubx in lgl− somatic clones induces transformation in the eye imaginal disc but not in its endogenous domain, namely, the haltere imaginal disc. Our results reveal that selector genes could behave as tumor drivers or inhibitors depending on the tissue contexts of their gains.

Clonal Hematopoiesis and Risk of Atherosclerotic Cardiovascular Disease

BackgroundClonal hematopoiesis of indeterminate potential (CHIP), which is defined as the presence of an expanded somatic blood-cell clone in persons without other hematologic abnormalities, is common among older persons and is associated with an increased risk of hematologic cancer. We previously found preliminary evidence for an association between CHIP and atherosclerotic cardiovascular disease, but the nature of this association was unclear.MethodsWe used whole-exome sequencing to detect the presence of CHIP in peripheral-blood cells and associated such presence with coronary heart disease using samples from four case–control studies that together enrolled 4726 participants with coronary heart disease and 3529 controls. To assess causality, we perturbed the function of Tet2, the second most commonly mutated gene linked to clonal hematopoiesis, in the hematopoietic cells of atherosclerosis-prone mice.ResultsIn nested case–control analyses from two prospective cohorts, carriers of CHIP had a risk of coronary heart disease that was 1.9 times as great as in noncarriers (95% confidence interval [CI], 1.4 to 2.7). In two retrospective case–control cohorts for the evaluation of early-onset myocardial infarction, participants with CHIP had a risk of myocardial infarction that was 4.0 times as great as in noncarriers (95% CI, 2.4 to 6.7). Mutations in DNMT3A, TET2, ASXL1, and JAK2 were each individually associated with coronary heart disease. CHIP carriers with these mutations also had increased coronary-artery calcification, a marker of coronary atherosclerosis burden. Hypercholesterolemia-prone mice that were engrafted with bone marrow obtained from homozygous or heterozygous Tet2 knockout mice had larger atherosclerotic lesions in the aortic root and aorta than did mice that had received control bone marrow. Analyses of macrophages from Tet2 knockout mice showed elevated expression of several chemokine and cytokine genes that contribute to atherosclerosis.ConclusionsThe presence of CHIP in peripheral-blood cells was associated with nearly a doubling in the risk of coronary heart disease in humans and with accelerated atherosclerosis in mice. (Funded by the National Institutes of Health and others.)