Heterozygous Mutant Research Articles

Generation of heterozygous PKD1 mutant pigs exhibiting early-onset renal cyst formation

AbstractAutosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disease, manifesting as the progressive development of fluid-filled renal cysts. In approximately half of all patients with ADPKD, end-stage renal disease results in decreased renal function. In this study, we used CRISPR-Cas9 and somatic cell cloning to produce pigs with the unique mutation c.152_153insG (PKD1insG/+). Pathological analysis of founder cloned animals and progeny revealed that PKD1insG/+ pigs developed many pathological conditions similar to those of patients with heterozygous mutations in PKD1. Pathological similarities included the formation of macroscopic renal cysts at the neonatal stage, number and cystogenic dynamics of the renal cysts formed, interstitial fibrosis of the renal tissue, and presence of a premature asymptomatic stage. Our findings demonstrate that PKD1insG/+ pigs recapitulate the characteristic symptoms of ADPKD.Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder characterized by the formation of cysts within the kidneys. The authors generated PKD1 heterozygous knockout (PKD1insG/+) pigs by CRISPR-Cas9 and somatic cell cloning techniques. The founder cloned animals and progeny showed the renal cyst formation from the neonatal stage, interstitial fibrosis of the renal tissue, and the presence of a premature asymptomatic stage. Their findings demonstrate that PKD1insG/+ pigs recapitulate the characteristic symptoms of ADPKD.

Deletion of Sf3b4 in Neural Crest Cells Encapsulates the Variable Expressivity of Craniofacial Abnormalities Observed in Nager and Rodriguez Syndrome Patients

Recently, both Nager syndrome and Rodriguez syndrome patients were identified to carry rare mutations in SF3B4. Both disorders affect the face as well as the limb including both hands and feet. Nager syndrome patients survive and exhibit smaller jaw bones, smaller cheek bones, cleft palate, hearing problems as well as downward slanted eyelids. However, Rodriguez syndrome is much more severe, and patients often die before or soon after birth. We hypothesized that craniofacial abnormalities associated with reduced SF3B4 levels is due to tissue‐specific expression and requirement of this gene in neural crest cells. To generate a conditional mutant mouse line for Sf3b4, we used CRISPR/Cas9 to insert LoxP sequences in intron 1 and 3 of this gene. To test our hypothesis, we mated Sf3b4conditional mutant mice to Wnt1‐Cre2 transgenic mice to delete exons 2 and 3 specifically in neural crest cells. Heterozygous mutant embryos from these matings were normal. Sf3b4L/L;Wnt1‐Cre2 embryos have brain and craniofacial abnormalities, including abnormal forebrain, midbrain and hindbrain, hypoplasia of the maxillomandibular region and midline cleft. Majority of these embryos die before birth and the few mutants that are born are indistinguishable from their wildtype littermates. Additionally, we generated Sf3b4L/‐;Wnt1‐Cre2 mutants with homozygous deletion of Sf3b4 in neural crest cells and heterozygous deletion of Sf3b4 in the body. These mutant embryos also had unfused frontonasal prominence and unfused and severely hypoplastic mandibular region. Sf3b4L/‐;Wnt1‐Cre2begin to die at E13.5 and none survive to birth. Thus, neural crest specific deletion of Sf3b4 in mice is able to model the craniofacial abnormalities presented in patients as well as capture the variable expressivity observed. Our model can further be used to uncover the splicing and molecular events regulated by SF3B4 during craniofacial development.

Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism rather than homocysteine increase the risk of ischemic stroke-associated executive dysfunction

Background: An executive dysfunction is a form of cognitive impairment commonly found in ischemic stroke patients with a significant impact on the patients' quality of life. The methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and homocysteine ​​are considered important risk factors for stroke and various forms of cognitive dysfunction. This study aimed to investigate the association between the MTHFR C677T polymorphism and serum homocysteine levels and the risk of ischemic stroke-associated executive dysfunction. Method: 87 ischemic stroke patients within the first three months of stroke onset in West Nusa Tenggara General Hospital, Siti Hajar Hospital, and Mataram General Hospital were recruited. Serum homocysteine levels were assessed using ELISA. The MTHFR C677T polymorphism was analyzed using the PCR-RFLP procedure. The executive function of the patients was evaluated using Trail Making Test Part-B, verbal fluency, and backward digit span tests. Results: The mean age of the subjects was 54.1 years. CT scan data revealed that 78.2% of subjects had a small infarct size. The MTHFR C677T polymorphism frequency was 25.3%, consisting of 2.3% homozygous and 23.0% heterozygous mutants. Multivariate logistic regression analysis showed that patients with MTHFR C677T polymorphism were more likely to have executive dysfunction than those with the wild-type genotype of the MTHFR gene (OR 4.53, 95% CI 1.06–19.27, p = 0.041). However, patients with hyperhomocysteinemia (≥13 μmol/l) were not associated with an increased risk of executive dysfunction. Conclusion: The MTHFR C677T polymorphism was the risk factor for ischemic stroke executive dysfunction.

The Ameliorating Effects of Apple Polyphenol Extract on High-Fat-Diet-Induced Hepatic Steatosis Are SIRT1-Dependent: Evidence from Hepatic-Specific SIRT1 Heterozygous Mutant C57BL/6 Mice

Apple polyphenol extract (APE) has been reported to possess protective effects against hepatic steatosis. To explore whether APE-induced alleviation of hepatic steatosis is SIRT1-dependent, the present study was carried out using wild-type and hepatic SIRT1 heterozygous mutant (Sirt1+/-) C57BL/6 mice. On consideration of the sex disparity related to hepatic steatosis morbidity, both male and female mice were included in the study. Six to eight week old mice were fed a high-fat diet (HFD) and randomly assigned to one of the following groups: (1) wild-type mice (wt+HFD), (2) Sirt1+/- mice (Sirt1+/-+HFD), and (3) Sirt1+/- mice with 500 mg/(kg·bw·d) APE intragastric administration (Sirt1+/-+HAP). HFD-induced weight gain and triglyceride accumulation was more prominent in Sirt1+/- mice in comparison to wild-type mice. Following APE treatment, these effects were significantly reduced along with the alleviation of hepatic steatosis via upregulated expression of SIRT1 at the protein and mRNA levels in both male and female mice. However, APE differentially regulated the genes related to lipid metabolism (Lkb1, Ampk, Hsl, Srebp-1c, Abcg1, and Cd36) in a sex-specific manner. Moreover, APE treatment altered gut microbiota composition, with an increased relative abundance of Akkermansia and a decreased Firmicutes/Bacterodetes ratio. Thus, our study provided new evidence supporting our hypothesis that APE-induced alleviation of hepatic steatosis is SIRT1-dependent.

CRISPR/Cas-9 induced knockout of myostatin gene improves growth and disease resistance in channel catfish (Ictalurus punctatus)

Channel catfish, Ictalurus punctatus, is the most produced aquaculture species in the United States, although production levels have decreased since their peak in 2003. Myostatin (mstn) regulates skeletal muscle growth and has been identified as an important gene for increasing body weight in aquaculture species. In this study, the effects of CRISPR/Cas9 knockout of the mstn gene in channel catfish were investigated. Three sgRNAs targeting exon 1 of the channel catfish myostatin gene were microinjected with Cas9 protein in embryos. A total of 209 fish survived to 6 mph after microinjection of Cas9 and sgRNA targeting exon 1 of the mstn gene over the 3 yr experiment (2017–2019) with an average mutation rate of 58%. Successful generation of myostatin knockout (MSTN KO) F1 heterozygotes was achieved in 2019 by individually mating two pairs of control females with MSTN homozygous KO males. The offspring of both families inherited the mutation at a mean rate of 88%. Growth was generally higher in MSTN mutants than controls at all life stages and environments. P1 MSTN mutants were 88% larger than controls at the stocker stage (100 to 200 g) and 27% larger than controls at market size. Heterozygous F1 mutants were 218% larger than controls at the stocker stage. MSTN mutants had reduced overall expression levels of mstn compared to controls. When challenged with Edwardsiella ictaluri, the causative agent of enteric septicemia of catfish, MSTN mutants performed equally or better than controls. With a high mutation rate and inheritance as well as improved growth and disease resistance, using MSTN gene-edited channel catfish could greatly benefit commercial farms.

A Nectin1 Mutant Mouse Model Is Resistant to Pseudorabies Virus Infection.

The present study generated nectin1-mutant mice with single amino acid substitution and tested the anti-pseudorabies virus (PRV) ability of the mutant mice, with the aim to establish a model for PRV-resistant livestock. A phenylalanine to alanine transition at position 129 (F129A) of nectin1 was introduced into the mouse genome to generate nectin1 (F129A) mutant mice. The mutant mice were infected with a field-isolated highly virulent PRV strain by subcutaneous injection of virus. We found that the homozygous mutant mice had significantly alleviated disease manifestations and decreased death rate and viral loading in serum and tissue compared with heterozygous mutant and wild-type mice. In addition to disease resistance, the homozygous mutant mice showed a defect in eye development, indicating the side effect on animals by only one amino acid substitution in nectin1. Results demonstrate that gene modification in nectin1 is an effective approach to confer PRV resistance on animals, but the mutagenesis pattern requires further investigation to increase viral resistance without negative effect on animal development.

Identification and Characterization of the MIKC-Type MADS-Box Gene Family in Brassica napus and Its Role in Floral Transition.

Increasing rapeseed yield has always been a primary goal of rapeseed research and breeding. However, flowering time is a prerequisite for stable rapeseed yield and determines its adaptability to ecological regions. MIKC-type MADS-box (MICK) genes are a class of transcription factors that are involved in various physiological and developmental processes in plants. To understand their role in floral transition-related pathways, a genome-wide screening was conducted with Brassica napus (B. napus), which revealed 172 members. Using previous data from a genome-wide association analysis of flowering traits, BnaSVP and BnaSEP1 were identified as candidate flowering genes. Therefore, we used the CRISPR/Cas9 system to verify the function of BnaSVP and BnaSEP1 in B. napus. T0 plants were edited efficiently at the BnaSVP and BnaSEP1 target sites to generate homozygous and heterozygous mutants with most mutations stably inherited by the next generation. Notably, the mutant only showed the early flowering phenotype when all homologous copies of BnaSVP were edited, indicating functional redundancy between homologous copies. However, no changes in flowering were observed in the BnaSEP1 mutant. Quantitative analysis of the pathway-related genes in the BnaSVP mutant revealed the upregulation of SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) and FLOWERING LOCUS T (FT) genes, which promoted early flowering in the mutant. In summary, our study created early flowering mutants, which provided valuable resources for early maturing breeding, and provided a new method for improving polyploid crops.

Knockout of lipoprotein lipase with CRISPR/Cas9 causes severe developmental defects and affects lipid deposition in Japanese medaka (Oryzias latipes)

In mammals, lipoprotein lipase (LPL) has been found to play an important role in lipid mentalism and deposition. LPL deficiency in humans (Homo sapiens) and mice (Mus musculus) tends to cause hypertriglyceridemia. The lpl gene is not expressed in adult mammalian liver, but is in adult fish liver. The functions provided by the lpl gene are diverse in vertebrates. Here, we knocked out the lpl gene in Japanese medaka (Oryzias latipes) with the CRISPR/Cas9 system. The lpl-knockout (KO) homozygous individuals showed severe developmental defects with an extremely emaciated and deformed body and only accounted for about 5% of the F2 fish. This is consistent with the findings in mice but disaccords with the results for zebrafish (Danio rerio). Compared with wild-type (WT) madaka, the mRNA level of lpl in lpl-KO heterozygous mutant was significantly higher in the muscle, showed no significant difference in the liver, and was significantly lower in the heart. Under lpl heterozygous deficiency, the relative area of Oil Red O and triglycerides (TG) level in the liver, heart and muscle tissue covaried with levels of lpl mRNA in medaka. The lpl heterozygous deficiency did not affect the levels of TG, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and total cholesterol (TC) in the plasma of medaka, which is inconsistent with the findings in mammals. In general, the lpl gene plays an important role in the growth and development and is closely related to lipid deposition of medaka.

Function analysis of GmELF3s in regulating soybean flowering time and circadian rhythm

<p id="C3">Soybean is a typical short-day crop. Photoperiod sensitivity seriously affects flowering time, yield, and planting range of soybean, but the mechanism underlying photoperiod and circadian rhythm regulation is still unclear. In <italic>Arabidopsis thaliana</italic>, ELF3, together with ELF4 and LUX, forms the ELF4-ELF3-LUX complex (Evening Complex, EC), which plays an important role in circadian rhythm and flowering time regulation. In this study, soybean mutants of <italic>Gmelf3a/j</italic>, <italic>Gmelf3b-1</italic>, and <italic>Gmelf3b-2 </italic>were obtained by CRISPR/Cas9 gene editing system. We found that GmELF3b-1 regulated the flowering time in soybean under long-day conditions by observing flowering phenotypes in these mutants. The phenotypes of heterozygous double mutants revealed that there was functional redundancy among GmELF3a/J, GmELF3b-1<italic>, </italic>and GmELF3b-2 in regulating flowering time of soybean. Through detecting the expression of circadian related genes in soybean by using qRT-PCR, it was found that the relative expression patterns of <italic>GmCAB</italic>, <italic>GmPRR9a</italic>, and <italic>GmPRR7a</italic> were changed in soybean. In summary, these results suggested that GmELF3a/J, GmELF3b-1, and GmELF3b-2 may regulate the circadian rhythm and flowering time through GmPRR9a and GmPRR7a in soybean.

Notch-dependent DNA cis-regulatory elements and their dose-dependent control of C. elegans stem cell self-renewal.

ABSTRACTA long-standing biological question is how DNA cis-regulatory elements shape transcriptional patterns during metazoan development. Reporter constructs, cell culture assays and computational modeling have made major contributions to answering this question, but analysis of elements in their natural context is an important complement. Here, we mutate Notch-dependent LAG-1 binding sites (LBSs) in the endogenous Caenorhabditis elegans sygl-1 gene, which encodes a key stem cell regulator, and analyze the consequences on sygl-1 expression (nascent transcripts, mRNA, protein) and stem cell maintenance. Mutation of one LBS in a three-element cluster approximately halved both expression and stem cell pool size, whereas mutation of two LBSs essentially abolished them. Heterozygous LBS mutant clusters provided intermediate values. Our results lead to two major conclusions. First, both LBS number and configuration impact cluster activity: LBSs act additively in trans and synergistically in cis. Second, the SYGL-1 gradient promotes self-renewal above its functional threshold and triggers differentiation below the threshold. Our approach of coupling CRISPR/Cas9 LBS mutations with effects on both molecular and biological readouts establishes a powerful model for in vivo analyses of DNA cis-regulatory elements.

Identification of Single-Nucleotide Polymorphisms Associated with Renal Dysfunction After Lung Transplantation Using Ethnic-Specific SNP Array

<h3>Purpose</h3> Renal dysfunction is a well-known long-term complication that could increase mortality after lung transplantation (LT). The proportion of severe renal dysfunction increases overtime to reach 24.6% within 10 years after LT. The development of severe renal dysfunction has been shown to be associated with increased mortality after LT. However, the association between single-nucleotide polymorphism (SNP) and renal dysfunction after LT has not been elucidated. In this study, we aimed to investigate SNPs associated with renal dysfunction after LT using the SNP array for the Japanese population, Japonica Array NEO (Toshiba, Japan), comprising a total of 66,883 markers. <h3>Methods</h3> We collected blood samples from 99 recipients after LT. First, among these, 34 qualified samples were genotyped using the SNP array. According to the homozygous and heterozygous mutant alleles of 162 SNPs associated with renal dysfunction, they were divided into two groups. The renal function tests, including creatinine and eGFR, were compared between the two groups in each SNP. Next, after identifying candidate SNPs, we investigated the association between the candidate SNPs and the renal function of all 99 recipients. Delta eGFR (ΔeGFR) was defined as the difference between the postoperative and preoperative baseline levels. <h3>Results</h3> A total of 8 SNPs (rs102275, rs10277115, rs174549, rs2980098, rs4690095, rs72719193, rs792064 and rs7956634) were identified as candidate SNPs associated with renal dysfunction after LT. Validation analysis of these 8 candidate SNPs in all 99 recipients showed that three SNPs (rs10277115, rs4690095, and rs792064) were associated with significant differences in the postoperative change of ΔeGFR after LT (Fig. 1). <h3>Conclusion</h3> Three SNPs, rs10277115, rs4690095 and rs792064, were associated with significant differences in eGFR in the long term and the development of renal dysfunction after LT.

Production of Germ Cell-Less Rainbow Trout by dead end Gene Knockout and their Use as Recipients for Germ Cell Transplantation.

In germ cell transplantation experiments, the use of sterile recipients that do not produce their own gametes is an important prerequisite. Triploidization and dnd gene knockdown (KD) methods have been widely used to produce sterile fish. However, triploidization does not produce complete sterility in some fish species, and gene KD is labor and time intensive since it requires microinjection into individual fertilized eggs. To overcome these problems, in this study, we generated homozygous mutants of the dead end (dnd) gene in rainbow trout (Oncorhynchus mykiss) using the clustered regulatory interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) system, analyzed their reproductive capacity, and evaluated their suitability as recipients for germ cell transplantation. By crossing F1 heterozygous mutants produced from founders subjected to genome editing, an F2 generation consisting of approximately 1/4 homozygous knockout mutants (dnd KO) was obtained. The dnd KO hatchlings retained the same number of primordial germ cells (PGCs) as the wild-type (WT) individuals, after which the number gradually decreased. At 1year of age, germ cells were completely absent in all analyzed individuals. To evaluate the dnd KO individuals as recipients for germ cell transplantation, germ cells prepared from donor individuals were transplanted into the abdominal cavity of dnd KO hatchlings. These cells migrated to the recipient gonads, where they initiated gametogenesis. The mature recipient individuals produced only donor-derived sperm and eggs in equivalent numbers to WT rainbow trout. These results indicate that dnd KO rainbow trout are suitable recipient candidates possessing a high capacity to nurse donor-derived germ cells.

411 Essential role for the neurodevelopmental disorder-linked gene, MEF2C, in inhibitory neuron function and neurotypical behaviors

OBJECTIVES/GOALS: The MEF2 family of transcription factors regulate gene expression controlling cell differentiation and synapse development. Mutations or deletions in the MEF2C gene cause a neurodevelopmental disorder that includes symptoms of autism spectrum disorder. In this study, we aim to study the role of MEF2C in GABAergic populations using an animal model. METHODS/STUDY POPULATION: MEF2C Haploinsufficiency Syndrome (MCHS) occurs when there is one functional allele and one disrupted allele of MEF2C. To study the role of MEF2C in GABAergic populations during mouse development, we bred Vgat (vesicular GABA transporter)-Cre mice, which express cre recombinase broadly in early developing GABAergic neurons, with a floxed Mef2c loss-of-function mouse to create offspring that are GABAergic cell-specific Mef2c heterozygous mutants (Mef2c cHetVgat-cre). We then subjected these mutants and littermate controls to a battery of tests measuring MCHS-relevant phenotypes, including spatial working memory, anxiety-like behavior, social preference, sensory sensitivity, and Pavlovian learning and memory. RESULTS/ANTICIPATED RESULTS: Mef2c cHetVgat-cre mice showed significant deficits in spatial working memory, social preference, and contextual fear memory, all of which are prefrontal cortex (PFC)-dependent behaviors. Interestingly, we noted that conditional Mef2c knockout mice (Mef2c cKOVgat-cre) showed embryonic and early postnatal lethality, probable seizures, and severe motor coordination problems, highlighting the importance of MEF2C function in GABAergic populations. DISCUSSION/SIGNIFICANCE: We hypothesize that MEF2C plays a cell-autonomous role in GABAergic cells to control the balance of excitatory and inhibitory synaptic transmission in the developing and mature brain, which in the Mef2c cHet mice might be critical for PFC-dependent learning and memory and sociability.

The solute carrier SLC15A4 is required for optimal trafficking of nucleic acid–sensing TLRs and ligands to endolysosomes

A function-impairing mutation (feeble) or genomic deletion of SLC15A4 abolishes responses of nucleic acid–sensing endosomal toll-like receptors (TLRs) and significantly reduces disease in mouse models of lupus. Here, we demonstrate disease reduction in homozygous and even heterozygous Slc15a4 feeble mutant BXSB male mice with a Tlr7 gene duplication. In contrast to SLC15A4, a function-impairing mutation of SLC15A3 did not diminish type I interferon (IFN-I) production by TLR-activated plasmacytoid dendritic cells (pDCs), indicating divergence of function between these homologous SLC15 family members. Trafficking to endolysosomes and function of SLC15A4 were dependent on the Adaptor protein 3 (AP-3) complex. Importantly, SLC15A4 was required for trafficking and colocalization of nucleic acid–sensing TLRs and their ligands to endolysosomes and the formation of the LAMP2+VAMP3+ hybrid compartment in which IFN-I production is initiated. Collectively, these findings define mechanistic processes by which SLC15A4 controls endosomal TLR function and suggest that pharmacologic intervention to curtail the function of this transporter may be a means to treat lupus and other endosomal TLR-dependent diseases.

Establishment of cytochrome P450 1a gene-knockout Javanese medaka, Oryzias javanicus, which distinguishes toxicity modes of the polycyclic aromatic hydrocarbons, pyrene and phenanthrene

Cytochrome P450 1a (Cyp1a) is an important enzyme for metabolism of organic pollutants. To understand its reaction to polycyclic aromatic hydrocarbons (PAHs), we knocked out this gene in a marine model fish, Javanese medaka, Oryzias javanicus, using the CRISPR/Cas 9 system. A homozygous mutant (KO) strain with a four-base deletion was established using an environmental DNA (eDNA)-based genotyping technique. Subsequently, KO, heterozygous mutant (HT), and wild-type (WT) fish were exposed to model pollutants, pyrene and phenanthrene, and survivorship and swimming behavior were analyzed. Compared to WT, KO fish were more sensitive to pyrene, suggesting that Cyp1a transforms pyrene into less toxic metabolites. Conversely, WT fish were sensitive to phenanthrene, suggesting that metabolites transformed by Cyp1a are more toxic than the original compound. HT fish showed intermediate results. Thus, comparative use of KO and WT fish can distinguish modes of pollutant toxicity, providing a deeper understanding of fish catabolism of environmental pollutants.

Development and Application of a High-Resolution Melting Analysis with Unlabeled Probes for the Screening of Short-Tailed Sheep TBXT Heterozygotes.

Simple SummaryTBXT (c.333G > C; c.334G > T) has been identified as a molecular genetic marker in short-tailed sheep. This paper describes a high-resolution melting (HRM) analysis using unlabeled probes and asymmetric PCR for the detection of genetic variants of TBXT in short-tailed sheep populations. The detection results of this method are consistent with those of Sanger sequencing and can help farmers with marker-assisted breeding.The short-tailed phenotype has long been considered one of the best traits for population genetic improvement in sheep breeding. In short-tailed sheep, not only is tail fat eliminated but also the pubic area is exposed due to the lack of a tail covering, giving them an advantage in reproduction. Recent studies have shown that two linked mutations in sheep TBXT at nucleotides 333 and 334 are associated with the short-tailed phenotype. In the population of short-tailed sheep, several heterozygous mutants of this gene are found. In our research, we used high-resolution melting (HRM) to identify homozygous and heterozygous genotypes in a flock of short-tailed sheep and compared the results with those of Sanger sequencing, which were identical. This demonstrates that our established HRM method, a rapid and inexpensive genotyping method, can be used to identify homozygous and heterozygous individuals in short-tailed sheep flocks.

Effect of the genetic mutant G71R in uridine diphosphate-glucuronosyltransferase 1A1 on the conjugation of bilirubin.

We aimed to investigate the effect of the genetic mutant G71R (c. 211G > A) in uridine diphosphate (UDP)-glucuronosyltransferase 1A1 (UGT1A1) on the glucuronidation of unconjugated bilirubin. The UGT1A1 wild-type and mutant G71R gene sequences were inserted into the lentiviral vector GV358 plasmid and then transfected into COS-7 cells. Real-time polymerase chain reaction and western blot analyses were used to determine mRNA and protein expression levels of UGT1A1, respectively. High-performance liquid chromatography was used to quantitate the levels of conjugated bilirubin. The results showed no significant difference in the mRNA and protein expression levels between the UGT1A1 wild-type and G71R homozygous and heterozygous mutants. The level of conjugated bilirubin reached a maximum in wild-type UGT1A1-transfected COS-7 cells. However, relative to the UGT1A1 wild-type, conjugated bilirubin concentrations were 71 and 22% with G71R heterozygous- and G71R homozygous-transfected COS-7 cells, respectively. In conclusion, we successfully established in vitro cell models of the UGT1A1 wild-type and the G71R homozygous and heterozygous mutants using a lentiviral vector. Furthermore, the catalytic activity for unconjugated bilirubin was lower in the mutant G71R than the UGT1A1 wild-type enzyme, and a weaker effect was observed in the homozygote.

Slc6a20a Heterozygous and Homozygous Mutant Mice Display Differential Behavioral and Transcriptomic Changes.

SLC6A20A is a proline and glycine transporter known to regulate glycine homeostasis and NMDA receptor (NMDAR) function in the brain. A previous study found increases in ambient glycine levels and NMDA receptor-mediated synaptic transmission in the brains of Slc6a20a-haploinsufficient mice, but it remained unknown whether Slc6a20a deficiency leads to disease-related behavioral deficits in mice. Here, we report that Slc6a20a heterozygous and homozygous mutant mice display differential behavioral phenotypes in locomotor, repetitive behavioral, and spatial and fear memory domains. In addition, these mice show differential transcriptomic changes in synapse, ribosome, mitochondria, autism, epilepsy, and neuron-related genes. These results suggest that heterozygous and homozygous Slc6a20a deletions in mice lead to differential changes in behaviors and transcriptomes.

Heterozygous Dnmt3a R878C induces expansion of quiescent hematopoietic stem cell pool

Somatic mutation of DNMT3A (DNA methyltransferase 3 alpha) is implicated in the development of a wide range of hematological disorders, including clonal hematopoiesis of indeterminate potential. To elucidate the functional roles of endogenous levels of a DNMT3A R882 mutant, we generated a novel Dnmt3a R878C conditional knock-in mouse model. In contrast to viable heterozygotes, mice homozygous for the Dnmt3a R878C mutation in the hematopoietic system were not viable (Dnmt3a R878C is homologous to human DNMT3A R882C). Hematopoietic cell-specific heterozygous expression of Dnmt3a R878C led to significant expansion of adult quiescent hematopoietic stem cells (HSCs); however, these mice had no hematological malignancies. The expanding HSC population in heterozygous Dnmt3a R878C knock-in mice had an accumulation of G0-phase cells. In contrast to aberrantly enhanced self-renewal capacity in vitro, heterozygous Dnmt3a R878C knock-in HSCs had no competitive repopulating advantage in vivo over wild-type HSCs. Considering the capacity of the heterozygous Dnmt3a R878C mutant for HSC pool expansion, our Dnmt3a R878C knock-in mouse line is a useful platform on which to dissect the pathophysiology of clonal hematopoiesis. This mouse line can also help to elucidate the biological and molecular actions of DNMT3A mutations in the malignant transformation of normal HSCs.

Mannose-Binding Lectin 2 Gene Polymorphism during Pandemic: COVID-19 Family.

Mannose-binding lectin 2 (MBL2) is a serine protease which is believed to be an important factor in the inherited immune system. In this article, we present a coronavirus disease 2019 (COVID-19) family of five patients: a 56-year-old father, a 51-year-old mother, two sons aged 23 and 21 years, and a 15-year-old daughter. According to the results of MBL2 rs1800450 variant analysis performed, the father had homozygous mutant, the mother had homozygous normal, and the three children had heterozygous mutant genotype. When we compared the clinical parameters and genotypes, MBL2 gene polymorphism plays a very important role in COVID-19 susceptibility and severe disease. The family, which makes up our study, is the proof of this situation, and it contains important implications for host factors and COVID-19.