Null Phenotype Research Articles

Generation and Initial Characterization of Three Murine Models with Altered Platelet TFPI Expression

Introduction: Tissue factor pathway inhibitor (TFPI) is an anticoagulant protein that inhibits tissue factor and prothrombinase during early stages of the procoagulant response. It is produced in alternatively spliced isoforms. In humans, TFPIα is within platelets and released upon activation and also is present in plasma, while TFPIβ is bound to the endothelial surface. Mice differ from humans in that they do not have TFPIα in plasma, making them an optimal model system for study of the function of platelet TFPIα. Studies of murine hematopoietic cell TFPI using fetal liver transplantation models have found that platelet TFPI dampens platelet accumulation in a growing thrombus following vascular injury and alters bleeding severity in mice with hemophilia. However, results of these studies are potentially confounded by altered TFPI expression on other hematopoietic cells, such as monocytes. To better understand the function of platelet TFPI, murine models of total TFPIα deletion (TFPIα KO), of platelet-specific TFPIα deletion (pTFPIα KO) and platelet-specific TFPIα over expression (pTFPIα high) were produced and characterized.Methods: A TFPIα deleted mouse was generated by inserting a stop codon within exon 10 of the TFPI gene effectively blocking translation of the highly conserved basic C-terminal region of TFPIα, but not altering TFPIβ. The PF4-Cre transgene was bred into the floxed-TFPI(K1) mouse to produce mice specifically lacking platelet TFPIα. A transgenic mouse over expressing platelet TFPIα under control of the GP1b promoter was produced. Mice were characterized for platelet and plasma TFPI antigen by ELISA, for activity by TF-FVIIa inhibition and whole blood platelet aggregation, and for bleeding by tail clip.Results: All 3 strains were viable and reproduced. Platelet TFPI antigen was decreased approximately 25-fold in the TFPIα KO and pTFPIα KO mice and elevated approximately 5-fold in the pTFPIα high mice with corresponding changes in TF-FVIIa inhibitory activity. Plasma TFPI antigen was no different between pTFPIα KO (20.6±4.4 nM) and wild type (21.5±6.2 nM) littermates. Plasma thrombin-antithrombin complex levels were not elevated in any strain. In tail clip bleeding time assays, there was no difference between pTFPIα KO (0.23±0.16 mg/ml Hb) and wild type (0.23±0.37 mg/ml Hb), but there was a trend towards increased blood loss in pTFPIα high mice (1.25±1.8 mg/ml Hb). The pTFPIα high mice also had altered whole blood platelet aggregation that was evident primarily in a prolonged time for initiation of aggregation with 6.50uM ADP (81±12 sec vs. 6.1±5.6 sec for control) or 0.8ug/ml collagen (35±17 sec vs. 16±21 sec for control). Finally, the pTFPIα high transgene was bred into TFPI heterozygous mice which were then bred to determine if over expression of platelet TFPIα would rescue the TFPI null embryonic lethal phenotype. However, no live TFPI null pups were observed following genotyping of over 50 pups from these matings.Conclusions: Three new mouse models of altered TFPI expression have been made providing valuable tools to study the role of platelet TFPI in bleeding and clotting disorders. Plasma TFPI is unchanged in mice lacking platelet TFPI demonstrating that platelet TFPI does not contribute to plasma TFPI in mice. Platelet TFPIα antigen and activity correlate in all three models. Deletion of the basic C-terminal region in TFPIα in the TFPIα KO mice produces a TFPIα hypomorphic mouse, with only trace amounts of truncated TFPIα present in platelets. This lack of TFPIα does not produce a generalized procoagulant state. The 5-fold excess TFPIα antigen in the pTFPIα high mice substantially delays the onset of platelet aggregation in whole blood assays initiated with collagen or ADP. Results from tail clip bleeding assays suggest that over expression of platelet TFPIα may prolong bleeding in adult mice, but it is not sufficient to rescue the embryonic lethality of TFPI null mice. DisclosuresMast:Novo Nordisk: Honoraria, Research Funding.

Effects of Genetic Polymorphisms on Leukocyte and Neutrophil Counts and Maximum Tolerated Dose of Hydroxyurea in Children with Sickle Cell Anemia

Background: Elevated total white blood cell (WBC) count is associated with increased morbidity and mortality in sickle cell anemia (SCA), and is a biomarker for disease severity. In addition, a higher WBC and absolute neutrophil count (ANC) have been associated with a higher maximum tolerated dose (MTD) for hydroxyurea in treated patients. Several single nucleotide polymorphisms (SNPs), especially variants in the Duffy Antigen Receptor for Chemokine (DARC) gene, influence WBC and ANC in the general population; however, their effects on children with SCA have not been reported.Objectives: To determine the effects of candidate SNPs on the baseline WBC and ANC in children with SCA; to identify novel genetic variants affecting WBC and ANC; and to investigate their effects on hydroxyurea MTD.Design/Method: Genomic DNA was analyzed from children with SCA enrolled in prospective trials involving hydroxyurea treatment, including: (1) Hydroxyurea Study of Long-Term Effects (HUSTLE, NCT 00305175); (2) Stroke With Transfusions Changing to Hydroxyurea (SWiTCH, NCT 00122980); and (3) Transcranial Doppler With Transfusions Changing to Hydroxyurea (TWiTCH, NCT 01425307). DNA samples were genotyped for 6 candidate SNPs that were previously reported to have a significant effect on the WBC and ANC in the general population, using a combination of PCR-based allelic discrimination and Sanger sequencing (Table). WBC and ANC phenotypes (n=429) were obtained at study enrollment, as well as hydroxyurea MTD values (n=224) for children receiving the drug. An additive model and correlation trend test was used to perform statistical testing. Whole exome sequencing (WES) analysis was performed after randomizing the entire cohort into a discovery (n=256) and validation group (n=127), to identify novel associations with WBC and ANC.Results: The average age (mean ± SD) of the entire cohort was 10.7 ± 4.1 years, with WBC = 13.8 ± 4.4 x 109/L and ANC = 7.6 ± 3.2 x 109/L. The DARC SNP rs2814778 regulating Duffy antigen expression had a minor allele frequency (MAF) of 15.1%, similar to published reports in African-American populations. After adjusting for age, children either homozygous or heterozygous for the A allele had significantly higher WBC and ANC, compared to G homozygotes known as "Duffy null" (14.6 vs. 13.5 x 109/L and 8.5 vs. 7.2 x 109/L, p=0.015 and p=0.001, respectively). For DARC rs12075, which distinguishes the major Duffy alleles, the G allele that results in Fya expression was associated with higher ANC than Fyb, 8.8 vs. 7.4 x 109/L, p=0.017. The hydroxyurea MTD was 25.6 ± 4.5 mg/kg/day for the treated cohort, which was associated with pre-treated WBC (p=0.009) and ANC (0.002), but with none of the DARC polymorphisms. An unbiased search using WES identified a total of 45,228 non-synonymous variants with allele frequency >1%, including 2,238 variants associated with WBC and ANC in the discovery group (p<.05). Following replication testing in the validation group, 64 variants maintained association (p<0.05). Of these, 11 were located near the DARC gene and likely are in linkage with this known potent modifier. Five additional variants in the ZFHX4, RAB11FIP1, MAN2B1, RP1L1, and CD109 genes had overall p-values <.005 and represent polymorphisms that may affect WBC and ANC.Table 1GeneSNPLocationMAFWBCANCBeta valuep valueBeta valuep valueDARCrs28147781q23.1511.020.0151.010.001DARCrs120751q23.0590.800.2031.090.017IFI16rs46576161q23.0691.240.0410.790.077PSMD3-CSFrs406532117q21.1.3860.390.2190.320.442CDK6rs4457q21.2.188-0.220.586-0.230.577CXCL2rs91314q13.3.202-0.260.506-0.160.172Candidate genes associated with WBC count. Beta value represents the average change in levels with each allele copy.Conclusions: Common genetic variants affecting WBC and ANC in the general population also modify the phenotype of children with SCA, and can explain some of the observed WBC variability. This analysis confirms that children with SCA with Duffy alleles have significantly higher WBC and ANC compared to Duffy null individuals. Notably, the effect of Duffy null phenotype on lower WBC and ANC persists despite the highly inflammatory state and leukocytosis commonly observed in SCA. Hydroxyurea MTD was positively correlated with baseline WBC and ANC, but was not influenced by DARC. WES results suggest additional novel gene variants that may influence the WBC and ANC in children with SCA. DisclosuresOff Label Use: Hydroxyurea is FDA approved for the treatment of sickle cell anemia in adults, but has not yet been approved in children.. Nottage:Janssen Pharmaceuticals: Employment. Ware:Bayer Pharmaceuticals: Consultancy; Eli Lilly: Other: DSMB membership; Biomedomics: Research Funding; Bristol Myers Squibb: Research Funding.

Caenorhabditis elegans glp-4 Encodes a Valyl Aminoacyl tRNA Synthetase.

Germline stem cell proliferation is necessary to populate the germline with sufficient numbers of cells for gametogenesis and for signaling the soma to control organismal properties such as aging. The Caenorhabditis elegans gene glp-4 was identified by the temperature-sensitive allele bn2 where mutants raised at the restrictive temperature produce adults that are essentially germ cell deficient, containing only a small number of stem cells arrested in the mitotic cycle but otherwise have a morphologically normal soma. We determined that glp-4 encodes a valyl aminoacyl transfer RNA synthetase (VARS-2) and that the probable null phenotype is early larval lethality. Phenotypic analysis indicates glp-4(bn2ts) is partial loss of function in the soma. Structural modeling suggests that bn2 Gly296Asp results in partial loss of function by a novel mechanism: aspartate 296 in the editing pocket induces inappropriate deacylation of correctly charged Val-tRNAval. Intragenic suppressor mutations are predicted to displace aspartate 296 so that it is less able to catalyze inappropriate deacylation. Thus glp-4(bn2ts) likely causes reduced protein translation due to decreased levels of Val-tRNAval. The germline, as a reproductive preservation mechanism during unfavorable conditions, signals the soma for organismal aging, stress and pathogen resistance. glp-4(bn2ts) mutants are widely used to generate germline deficient mutants for organismal studies, under the assumption that the soma is unaffected. As reduced translation has also been demonstrated to alter organismal properties, it is unclear whether changes in aging, stress resistance, etc. observed in glp-4(bn2ts) mutants are the result of germline deficiency or reduced translation.

Feedback Mechanisms Regulate Ets Variant 2 (Etv2) Gene Expression and Hematoendothelial Lineages

Etv2 is an essential transcriptional regulator of hematoendothelial lineages during embryogenesis. Although Etv2 downstream targets have been identified, little is known regarding the upstream transcriptional regulation of Etv2 gene expression. In this study, we established a novel methodology that utilizes the differentiating ES cell and embryoid body system to define the modules and enhancers embedded within the Etv2 promoter. Using this system, we defined an autoactivating role for Etv2 that is mediated by two adjacent Ets motifs in the proximal promoter. In addition, we defined the role of VEGF/Flk1-Calcineurin-NFAT signaling cascade in the transcriptional regulation of Etv2. Furthermore, we defined an Etv2-Flt1-Flk1 cascade that serves as a negative feedback mechanism to regulate Etv2 gene expression. To complement and extend these studies, we demonstrated that the Flt1 null embryonic phenotype was partially rescued in the Etv2 conditional knockout background. In summary, these studies define upstream and downstream networks that serve as a transcriptional rheostat to regulate Etv2 gene expression.

Protein O-Glucosyltransferase 1 (POGLUT1) Promotes Mouse Gastrulation through Modification of the Apical Polarity Protein CRUMBS2.

Crumbs family proteins are apical transmembrane proteins with ancient roles in cell polarity. Mouse Crumbs2 mutants arrest at midgestation with abnormal neural plate morphology and a deficit of mesoderm caused by defects in gastrulation. We identified an ENU-induced mutation, wsnp, that phenocopies the Crumbs2 null phenotype. We show that wsnp is a null allele of Protein O-glucosyltransferase 1 (Poglut1), which encodes an enzyme previously shown to add O-glucose to EGF repeats in the extracellular domain of Drosophila and mammalian Notch, but the role of POGLUT1 in mammalian gastrulation has not been investigated. As predicted, we find that POGLUT1 is essential for Notch signaling in the early mouse embryo. However, the loss of mouse POGLUT1 causes an earlier and more dramatic phenotype than does the loss of activity of the Notch pathway, indicating that POGLUT1 has additional biologically relevant substrates. Using mass spectrometry, we show that POGLUT1 modifies EGF repeats in the extracellular domain of full-length mouse CRUMBS2. CRUMBS2 that lacks the O-glucose modification fails to be enriched on the apical plasma membrane and instead accumulates in the endoplasmic reticulum. The data demonstrate that CRUMBS2 is the target of POGLUT1 for the gastrulation epithelial-to-mesenchymal transitions (EMT) and that all activity of CRUMBS2 depends on modification by POGLUT1. Mutations in human POGLUT1 cause Dowling-Degos Disease, POGLUT1 is overexpressed in a variety of tumor cells, and mutations in the EGF repeats of human CRUMBS proteins are associated with human congenital nephrosis, retinitis pigmentosa and retinal degeneration, suggesting that O-glucosylation of CRUMBS proteins has broad roles in human health.

A spontaneous segmental deletion from chromosome arm 3DL enhances Fusarium head blight resistance in wheat.

Much effort has been directed at identifying sources of resistance to Fusarium head blight (FHB) in wheat. We sought to identify molecular markers for what we hypothesized was a new major FHB resistance locus originating from the wheat cultivar 'Freedom' and introgressed into the susceptible wheat cultivar 'USU-Apogee'. An F2:3 mapping population from a cross between Apogee and A30, its BC4 near-isoline exhibiting improved FHB resistance, was evaluated for resistance. The distribution of FHB resistance in the population approximated a 1:3 moderately resistant : moderately susceptible + susceptible ratio. Separate disease evaluations established that A30 accumulated less deoxynivalenol and yielded a greater proportion of sound grain than Apogee. Molecular mapping revealed that the FHB resistance of A30 is associated with molecular markers on chromosome arm 3DL that exhibit a null phenotype in A30 but are present in both Apogee and Freedom, indicating a spontaneous deletion occurred during the development of A30. Aneuploid analysis revealed that the size of the deleted segment is approximately 19% of the arm's length. Our results suggest that the deleted interval of chromosome arm 3DL in Apogee may harbor FHB susceptibility genes that promote disease spread in infected spikes, and that their elimination increases FHB resistance in a novel manner.

The WOPR Domain Protein OsaA Orchestrates Development in Aspergillus nidulans.

Orchestration of cellular growth and development occurs during the life cycle of Aspergillus nidulans. A multi-copy genetic screen intended to unveil novel regulators of development identified the AN6578 locus predicted to encode a protein with the WOPR domain, which is a broadly present fungi-specific DNA-binding motif. Multi-copy of AN6578 disrupted the normal life cycle of the fungus leading to enhanced proliferation of vegetative cells, whereas the deletion resulted in hyper-active sexual fruiting with reduced asexual development (conidiation), thus named as osaA (Orchestrator of Sex and Asex). Further genetic studies indicate that OsaA balances development mainly by repressing sexual development downstream of the velvet regulator VeA. The absence of osaA is sufficient to suppress the veA1 allele leading to the sporulation levels comparable to veA + wild type (WT). Genome-wide transcriptomic analyses of WT, veA1, and ΔosaA veA1 strains by RNA-Seq further corroborate that OsaA functions in repressing sexual development downstream of VeA. However, OsaA also plays additional roles in controlling development, as the ΔosaA veA1 mutant exhibits precocious and enhanced formation of Hülle cells compared to WT. The OsaA orthologue of Aspergillus flavus is able to complement the osaA null phenotype in A. nidulans, suggesting a conserved role of this group of WOPR domain proteins. In summary, OsaA is an upstream orchestrator of morphological and chemical development in Aspergillus that functions downstream of VeA.

Regulation of arsenite oxidation by the phosphate two-component system PhoBR in Halomonas sp. HAL1.

Previously, the expression of arsenite [As(III)] oxidase genes aioBA was reported to be regulated by a three-component regulatory system, AioXSR, in a number of As(III)-oxidizing bacterial strains. However, the regulation mechanism is still unknown when aioXSR genes are absent in some As(III)-oxidizing bacterial genomes, such as in Halomonas sp. HAL1. In this study, transposon mutagenesis and gene knock-out mutation were performed, and two mutants, HAL1-phoR931 and HAL1-▵phoB, were obtained in strain HAL1. The phoR and phoB constitute a two-component system which is responsible for phosphate (Pi) acquisition and assimilation. Both of the mutants showed negative As(III)-oxidation phenotypes in low Pi condition (0.1 mM) but not under normal Pi condition (1 mM). The phoBR complementation strain HAL1-▵phoB-C reversed the mutants' null phenotypes back to wild type status. Meanwhile, lacZ reporter fusions using pCM-lacZ showed that the expression of phoBR and aioBA were both induced by As(III) but were not induced in HAL1-phoR931 and HAL1-▵phoB. Using 15 consensus Pho box sequences, a putative Pho box was found in the aioBA regulation region. PhoB was able to bind to the putative Pho box in vivo (bacterial one-hybrid detection) and in vitro (electrophoretic mobility gel shift assay), and an 18-bp binding sequence containing nine conserved bases were determined. This study provided the evidence that PhoBR regulates the expression of aioBA in Halomonas sp. HAL1 under low Pi condition. The new regulation model further implies the close metabolic connection between As and Pi.

Immunophenotypic Analysis in Early Müllerian Serous Carcinogenesis.

Studies on the immunophenotypes of early forms of serous carcinoma arising from female genital tract are limited. We aimed to examine p53, p16(Ink4a), estrogen receptor (ER), progesterone receptor (PR), ERBB2, WT1, and Ki-67 protein expression in endometrial intraepithelial carcinoma (n=29), serous tubal intraepithelial lesion (n=4) and carcinoma (STIC, n=10), and the putative precursor p53 signature (n=11). Among endometrial intraepithelial carcinoma, 80% demonstrated p53 overexpression and 10% were consistent with a null phenotype. p16(Ink4a) immunostaining were observed in all endometrial intraepithelial carcinoma cases. ER, PR, ERBB2, and WT1 were positive in 54%, 25%, 11%, and 18% of cases, respectively. STIC cases demonstrated p53 overexpression and null phenotype in 90% and 10%, respectively. All STIC cases were p16(Ink4a) and WT1 positive, whereas ER and PR were positive in 70% and 20%, respectively. All STICs were negative for ERBB2. Among serous tubal intraepithelial lesion cases, 75% demonstrated p53 overexpression and 25% a null phenotype. p53 was positive in all 11 p53 signature cases, whereas p16(Ink4a) was universally negative. Finally, ER and PR were positive in 100% and 73% of p53 signature cases, respectively. These results suggest that p16(Ink4a) has a role in early Müllerian serous carcinogenesis but is absent in the earliest noncommitted lesion. p16(Ink4a) immunohistochemistry can be used as an adjunct confirmatory tool in p53-null cases with limited surface area.

Molecular Reproduction &amp; Development Volume 82, Issue 9, September 2015 cover image

Molecular Reproduction and DevelopmentVolume 82, Issue 9 p. C1-C1 On the CoverFree Access Molecular Reproduction & Development Volume 82, Issue 9, September 2015 cover image First published: 16 September 2015 https://doi.org/10.1002/mrd.22404AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract Gene knockout animals are important to analyze gene function, but understanding gene function in adults can be confounded by embryo-lethal or null phenotypes associated with early gene knockouts. Willems et al. (this issue) circumvent this issue using lentiviral particles containing Cre recombinase and a red fluorescent protein (tRFP635) (red) to examine the role of androgen receptor (green) specifically in adult Sertoli cells. Their studies demonstrate that Sertoli cell androgen receptor signaling in adulthood is essential for spermatogenesis. Volume82, Issue9September 2015Pages C1-C1 RelatedInformation

Extra-intestinal calcium handling contributes to normal serum calcium levels when intestinal calcium absorption is suboptimal

The active form of vitamin D, 1,25(OH)2D, is a crucial regulator of calcium homeostasis, especially through stimulation of intestinal calcium transport. Lack of intestinal vitamin D receptor (VDR) signaling does however not result in hypocalcemia, because the increased 1,25(OH)2D levels stimulate calcium handling in extra-intestinal tissues. Systemic VDR deficiency, on the other hand, results in hypocalcemia because calcium handling is impaired not only in the intestine, but also in kidney and bone. It remains however unclear whether low intestinal VDR activity, as observed during aging, is sufficient for intestinal calcium transport and for mineral and bone homeostasis. To this end, we generated mice that expressed the Vdr exclusively in the gut, but at reduced levels. We found that ~15% of intestinal VDR expression greatly prevented the Vdr null phenotype in young-adult mice, including the severe hypocalcemia. Serum calcium levels were, however, in the low-normal range, which may be due to the suboptimal intestinal calcium absorption, renal calcium loss, insufficient increase in bone resorption and normal calcium incorporation in the bone matrix. In conclusion, our results indicate that low intestinal VDR levels improve intestinal calcium absorption compared to Vdr null mice, but also show that 1,25(OH)2D-mediated fine-tuning of renal calcium reabsorption and bone mineralization and resorption is required to maintain fully normal serum calcium levels.

A Novel Frameshift Mutation in SLC2A1 Associated with a Mild form of Glucose Transporter Type 1-Related Movement Disorder

The phenotypic spectrum of glucose transporter type 1 (GLUT1) deficiency syndrome is now known to be a continuum that includes the classic phenotype as well as atypical childhood absence epilepsy, myoclonic astatic epilepsy, and paroxysmal nonepileptic findings such as intermittent ataxia, choreoathetosis, dystonia, and alternating hemiplegia. We report the case of a mentally normal child with history of infantile seizures, which remitted but later developed nonepileptic movement disorder, responsive to carbohydrate intake, with a novel frameshift mutation (c.1344_1347delCTAC p.Y449fs) in the last exon of the GLUT1 gene. This case further broadens the phenotypic spectrum of GLUT1 deficiency syndrome. We provide evidence from this case and previous reports that mutations affecting the length and composition of the intracellular C-terminal domain of the GLUT1 protein have a variable and somewhat unpredictable range of pathological effects. These range from null phenotypes associated with C-terminal domain absence, to milder presentations associated with C-terminal domains comprising partially and (in this case study) completely abnormal amino acid sequences.

Abstract 416: B-Raf Loss Suppresses Extracellular-Regulated Kinase Activation and Cardiomyocyte Proliferation

Objectives: The postnatal heart does not retain the proliferative capacity it had during fetal life. Unlike large mammals, murine cardiomyocytes (CM) continue to divide into the first week of life before terminal differentiation and binucleation. We hypothesized that B-Raf regulates ERK activation in newborn CM and that loss of B-Raf suppresses cyclin levels and reduced proliferation. To test this, we determined whether loss of B-Raf disrupts the ERK (extracellular-regulated kinase) cascade and impairs CM growth. Methods: CM specific knockout (KO) of B-Raf was generated using CRE/lox (floxed B-Raf x αMHC CRE) resulting in a truncated, unstable B-Raf and a null phenotype. KO mice (α-MHC-CRE / B-Raf lox/lox ) were compared to CRE negative / B-Raf lox/lox mice (wild type; WT). Hearts from 3d and 8d old pups were harvested for molecular analysis of B-Raf signaling and cell cycle markers. Hearts from 3d old pups were harvested and CMs isolated for culture using a trypsin/DNAse digestion. The cells were treated with Isoproterenol (Iso;10uM), forskolin (20uM), and IGF-1 (1ng/ml) for 15 min to determine if the loss of B-Raf results in reduced activation of ERK. Results: Heart weight to body weight (HW/BW) ratio was less in 3d KO versus 3d WT (n=50, p&lt;0.05). HW/BW ratio became greater in 8d KO; there was no difference in 3d and 8d HW/BW in WT animals. Baseline B-Raf and phosphorylated ERK levels were reduced in KO hearts (*p&lt;0.05). Cell cycle inhibitors p21 and p53 were increased in 3d KO hearts with decreased levels of all cyclins (p&lt;0.05). In 8d KO hearts, increased p21, p27, and p53 expression was accompanied with increased cyclin levels (p&lt;0.05). In vitro ERK activation was blunted in KO CMs by forskolin and Iso compared to IGF-1. Conclusions: ERK activation was suppressed in KO hearts resulting in smaller newborn hearts but which exceeded normal HW/BW by 8d. This is may represent premature hypertrophy as the proliferative period of CM development had ended. Cell cycle analysis supports reduced CM mitotis among 8d CM. Such early disturbances in normal CM growth may increase susceptibility for reduced cardiac function in the face of increased postnatal load stress.

FY*A silencing by the GATA-motif variant FY*A(-69C) in a Caucasian family.

The c.1-67C variant polymorphism in a GATA motif of the FY promoter is known to result in erythroid-specific FY silencing, that is, in Fy(a-) and Fy(b-) phenotypes. A Caucasian donor presented with the very rare Fy(a-b-) phenotype and was further investigated. Genomic DNA was analyzed by sequencing to identify the cause of the Fy(a-b-) phenotype. Samples were collected from some of his relatives to establish a correlation between the serology and genotyping results. Red blood cells were analyzed by gel column agglutination and flow cytometry. Genomic DNA was analyzed on genotyping microarrays, by DNA sequencing and by allele-specific PCR. In the donor, a single-nucleotide polymorphism T>C within the GATA motif was found at Position c.1-69 of the FY promoter and shown to occur in the FY*A allele. His genotype was found to be FY*A(-69C), FY*BW.01. In six FY*A/FY*B heterozygous members of the family, a perfect correlation was found between the presence vs. absence of the FY*A(-69C) variant allele and a Fy(a-) vs. Fy(a+) phenotype. The location of the c.1-69C polymorphism in a GATA motif whose disruption is known to result in a Fy null phenotype, together with the perfect correlation between the presence of the FY*A(-69C) allele and the Fy(a-) phenotype support a cause-effect relationship between the two.

The gene encoding the mouse contactin-1 axonal glycoprotein is regulated by the collier/Olf1/EBF family early B-Cell factor 2 transcription factor.

The Contactin-1 axonal glycoprotein (formerly F3/Contactin) plays a relevant role in cerebellar ontogenesis, as shown in Contactin-1 KO-mice and in transgenic mice misexpressing the corresponding cDNA from a heterologous promoter. Likewise, null mutant mice for the Collier/Olf1/Early B-cell family transcription factor EBF2, in which Purkinje neuron development is primarily affected, exhibit abnormalities in cerebellar corticogenesis. Here, to evaluate the contribution to the Ebf2 null phenotype of changes in the profile of Contactin-1, we study its expression in Ebf2 null mice. In addition, we explore the activation profile of the Cntn1 gene promoter upon transferring the Ebf2 mutation to transgenic mice expressing an enhanced green fluorescent protein reporter under control of Cntn1 gene regulatory sequences. In Ebf2 null mice, Contactin-1 protein expression and Cntn1 gene promoter activity are both downregulated during embryonic and early postnatal cerebellar development, both in the rostral and caudal folia, while in the latter an upregulation is observed at postnatal day 8. In vitro, vectors driving EBF1,2,3 transcription factors from a cytomegalovirus (CMV) promoter transactivate a Cntn1-Choline acetyltransferse (CAT) promoter-reporter construct in cotransfection assays and, accordingly, by chromatin immunoprecipitation, we show that the Cntn1 gene 5' flanking region is bound by the EBF2 transcription factor, consistent with the evidence that this region bears the cognate deoxyribonucleic acid (DNA) consensus sequences. These data indicate that Contactin-1 expression is dependent upon EBF factors, suggesting that the Cntn1 gene belongs to the expanding regulatory cascade driven by these transcriptional regulators so that changes in its activation may contribute to the phenotype of Ebf2 null mutant mice.

Intersex (ix) mutations of Drosophila melanogaster cause nonrandom cell death in genital disc and can induce tumours in genitals in response to decapentaplegic (dpp(disk)) mutations.

In Drosophila melanogaster, the intersex (ix) is a terminally positioned gene in somatic sex determination hierarchy and function with the female specific product of double sex (DSX(F)) to implement female sexual differentiation. The null phenotype of ix is to transform diplo-X individuals into intersexes while leaving haplo-X animals unaffected. This study on the effect of different intersex mutations on genital disc development provides the following major results: (i) similar range of a characteristic array of morphological structures (from almost double sex terminalia to extreme reduction of terminal appendages) was displayed by the terminalia of XX ix(1)/ix(1) , XX ix(2)/ix(2) and XX ix(5)/ix(5) individuals; (ii) an increased number of apoptotic cells were found to occur in a localized manner in mature third instar larval genital discs of ix individuals; (iii) ix mutations can induce high frequency of neoplastic tumours in genitals in the presence of decapentaplegic (dpp(disk)) mutations; and (iv) heteroallelic combinations of dpp(disk) mutations can also induce tumours in intersex genitals with variable expressivity. On the basis of these findings, we suggest that: (i) loss of function of ix causes massive cell death in both male and female genital primordia of genital discs, resulting phenotype mimicking in male and female characteristics in genitals; and (ii) at the discs, the apoptotic cells persist as 'undead' cells that can induce oncogenic transformation in the neighbouring disc cells when dpp signalling is blocked or reduced by dpp(disk) mutations.

A library of MiMICs allows tagging of genes and reversible, spatial and temporal knockdown of proteins in Drosophila.

Here, we document a collection of ∼7434 MiMIC (Minos Mediated Integration Cassette) insertions of which 2854 are inserted in coding introns. They allowed us to create a library of 400 GFP-tagged genes. We show that 72% of internally tagged proteins are functional, and that more than 90% can be imaged in unfixed tissues. Moreover, the tagged mRNAs can be knocked down by RNAi against GFP (iGFPi), and the tagged proteins can be efficiently knocked down by deGradFP technology. The phenotypes associated with RNA and protein knockdown typically correspond to severe loss of function or null mutant phenotypes. Finally, we demonstrate reversible, spatial, and temporal knockdown of tagged proteins in larvae and adult flies. This new strategy and collection of strains allows unprecedented in vivo manipulations in flies for many genes. These strategies will likely extend to vertebrates.

Systematic analysis on the GSTM1 null phenotype and prostate cancer risk in Chinese people.

Glutathione S-transferase M 1 (GSTM1) is implicated as a risk factor for prostate cancer. However, this issue is not clear in Chinese population. This systemic analysis was conducted to evaluate the effect of GSTM1 null genotypes on prostate cancer risk in Chinese. Published studies investigating the associations between GSTM1 null genotypes and the risk of prostate cancer in China were identified by using a predefined search strategy. Main statisticals were pooled and estimated according to the primarily reported data. The prevalence of the GSTM1 null genotype was higher in prostate cancer patients than in controls, with significance. The GSTM1 null genotypes is associated with increased risk of prostate cancer in Chinese.

Plant stem cell maintenance by transcriptional cross-regulation of related receptor kinases.

The CLAVATA3 (CLV3)-CLAVATA1 (CLV1) ligand-receptor kinase pair negatively regulates shoot stem cell proliferation in plants. clv1 null mutants are weaker in phenotype than clv3 mutants, but the clv1 null phenotype is enhanced by mutations in the related receptor kinases BARELY ANY MERISTEM 1, 2 and 3 (BAM1, 2 and 3). The basis of this genetic redundancy is unknown. Here, we demonstrate that the apparent redundancy in the CLV1 clade is in fact due to the transcriptional repression of BAM genes by CLV1 signaling. CLV1 signaling in the rib meristem (RM) of the shoot apical meristem is necessary and sufficient for stem cell regulation. CLV3-CLV1 signaling in the RM represses BAM expression in wild-type Arabidopsis plants. In clv1 mutants, ectopic BAM expression in the RM partially complements the loss of CLV1. BAM regulation by CLV1 is distinct from CLV1 regulation of WUSCHEL, a proposed CLV1 target gene. In addition, quadruple receptor mutants are stronger in phenotype than clv3, pointing to the existence of additional CLV1/BAM ligands. These data provide an explanation for the genetic redundancy seen in the CLV1 clade and reveal a novel feedback operating in the control of plant stem cells.

Kidd blood group system: a review

Abstract The Kidd blood group system has been recognized as clinically important in red blood cell (RBC) serology since its identification in 1951. Forty years later, the JK glycoprotein was determined to be a product of SCL14A1 and was identical to the urea transport protein UT-B produced by HUT11A. The functional role of the protein as a urea transporter in RBCs and kidney has been well documented. The polymorphism responsible for the antithetical antigens Jka and Jkb was identified in 1994 as c.838G&gt;A (p. Asp280Asn). Recent discoveries have expanded the system to include 23 variant alleles recognized by the International Society of Blood Transfusion that silence the protein expression and 7 variant alleles presumably producing weak or partial JK antigens. Null phenotypes have been identified in individuals of several populations including those of African, Indian, and Chinese decent, in addition to the well-documented findings in the Polynesian and Finnish populations. This review will examine the historical information about the antigens and antibodies of the JK system as well as catalog the variations of the JK gene. Immunohematology 2015;31:29–35.