Identify Sequence Variants Research Articles

Engineering GID4 for use as an N-terminal proline binder via directed evolution.

Nucleic acid sequencing technologies have gone through extraordinary advancements in the past several decades, significantly increasing throughput while reducing cost. To create similar advancement in proteomics, numerous approaches are being investigated to advance protein sequencing. One of the promising approaches uses N-terminal amino acid binders (NAABs), also referred to as recognizers, that selectively can identify amino acids at the N-terminus of a peptide. However, there are only a few engineered NAABs currently available that bind to specific amino acids and meet the requirements of a biotechnology reagent. Therefore, additional NAABs need to be identified and engineered to enable confident identification and, ultimately, de novo protein sequencing. To fill this gap, a human protein GID4 was engineered to create a NAAB for N-terminal proline (Nt-Pro). While native GID4 binds Nt-Pro, its binding is weak (µmol/L) and greatly influenced by the identity of residues following the Nt-Pro. Through directed evolution, yeast-surface display, and fluorescence-activated cell sorting, we identified sequence variants of GID4 with increased binding response to Nt-Pro. Moreover, variants with an A252V mutation showed a reduced influence from residues in the second and third positions of the target peptide when binding to Nt-Pro. The workflow outlined here is shown to be a viable strategy for engineering NAABs, even when starting from native Nt-binding proteins whose binding is strongly impacted by the identity of residues following Nt-amino acid.

7080 Copy Number Variation (CNV) in Self-Limited Delayed Puberty (SLDP)

Abstract Disclosure: Y. Al-Sayed: None. M. Ishida: None. C.L. Hall: None. S. Howard: None. SLDP is where the onset of puberty is more than 2-2.5 standard deviations later than the population mean age and is often familial with strong genetic determinants. The reproductive axis is regulated by gonadotropin-releasing hormone (GnRH), which plays a crucial role in initiating puberty and maintaining fertility through its pulsatile secretion. Disruption in GnRH neuron development or hypothalamic function can lead to DP. UK Biobank data has identified negative health outcomes associated with SLDP including early menopause/andropause and cognitive and psychosocial disabilities. Consequently, there has been extensive research to investigate genes affecting the hypothalamic-pituitary-gonadal (HPG) axis that might be implicated in the pathogenesis of DP by our group and others which has identified sequence variation contributing to the aetiology of SLDP. However, factors beyond nucleotide variations, such as epigenetic changes and CNVs can also lead to pubertal timing disorders. Moreover, CNVs are seen in multiple individuals (n=92) from the Deciphering Developmental Disorders study (https://www.deciphergenomics.org) with a phenotype including DP (HP:0000823). We performed whole genome sequencing on 49 probands with SLDP and subsequently, analysed the data for CNV. The data was initially called, annotated, filtered then partitioned for classification of CNVs using a command-line tool that implements the ACMG guidelines to evaluate the pathogenicity of germline duplications and deletions. Using an unbiased candidate gene approach, we identified several deletions that affected 60 known/predicted dosage sensitive genes and combines with functional enrichment analysis; This approach revealed potential molecular pathways and biological processes involved in the pathogenesis of SLDP, including histone acetylation, and neural plate development. To refine our findings, we applied additional filters, including known HPG axis genes, GWAS loci associated with pubertal timing, decipher CNV tracks, and DP gene panels, to narrow down large number of rare predicted damaging CNVs and prioritize those with potential relevance to DP. Our study highlights the potential role of CNVs in DP and expands our understanding of the molecular pathways and biological processes involved in this condition, shedding light on the complex mechanisms underlying DP. Presentation: 6/2/2024

9205 Copy Number Variation (CNV) in Self-Limited Delayed Puberty (SLDP)

Abstract Disclosure: Y. Al-Sayed: None. M. Ishida: None. C.L. Hall: None. S.R. Howard: None. SLDP is where the onset of puberty is more than 2-2.5 standard deviations later than the population mean age and is often familial with strong genetic determinants. The reproductive axis is regulated by gonadotropin-releasing hormone (GnRH), which plays a crucial role in initiating puberty and maintaining fertility through its pulsatile secretion. Disruption in GnRH neuron development or hypothalamic function can lead to DP. UK Biobank data has identified negative health outcomes associated with SLDP including early menopause/andropause and cognitive and psychosocial disabilities. Consequently, there has been extensive research to investigate genes affecting the hypothalamic-pituitary-gonadal (HPG) axis that might be implicated in the pathogenesis of DP by our group and others which has identified sequence variation contributing to the aetiology of SLDP. However, factors beyond nucleotide variations, such as epigenetic changes and CNVs can also lead to pubertal timing disorders. Moreover, CNVs are seen in multiple individuals (n=92) from the Deciphering Developmental Disorders study (https://www.deciphergenomics.org) with a phenotype including DP (HP:0000823). We performed whole genome sequencing on 49 probands with SLDP and subsequently, analysed the data for CNV. The data was initially called, annotated, filtered then partitioned for classification of CNVs using a command-line tool that implements the ACMG guidelines to evaluate the pathogenicity of germline duplications and deletions. Using an unbiased candidate gene approach, we identified several deletions that affected 60 known/predicted dosage sensitive genes and combines with functional enrichment analysis; This approach revealed potential molecular pathways and biological processes involved in the pathogenesis of SLDP, including histone acetylation, and neural plate development. To refine our findings, we applied additional filters, including known HPG axis genes, GWAS loci associated with pubertal timing, decipher CNV tracks, and DP gene panels, to narrow down large number of rare predicted damaging CNVs and prioritize those with potential relevance to DP. Our study highlights the potential role of CNVs in DP and expands our understanding of the molecular pathways and biological processes involved in this condition, shedding light on the complex mechanisms underlying DP. Presentation: 6/2/2024

At the core of salinity: Divergent transcriptomic responses to neutral and alkaline salinity in Arabidopsis thaliana

In the context of current climate change, alkaline salinity is increasingly challenging crop yields, especially in arid and semiarid regions. Alkaline salinity is more detrimental to plant performance than neutral salinity and tolerance to neutral salinity may not confer tolerance to alkaline salinity. The mechanisms behind are still poorly understood. This study aims to identify physiological and genetic traits underlying this differential tolerance to neutral and alkaline salinity by exploiting the variation present in natural populations (demes) of Arabidopsis thaliana. Growth, photosynthesis, phytohormone and mineral nutrient profiles, plant water status and transcriptomic changes were analyzed in four demes with contrasting tolerance to neutral and alkaline salinity. Results of this novel holistic approach suggest low internal Fe use efficiency caused by bicarbonate as a driver of enhanced sensitivity to alkaline salinity in plants adapted to neutral salinity prompting photosynthesis inhibition and alteration of the plant’s carbon budget for primary and secondary metabolism. Moreover, alkaline salinity specifically altered the auxin and jasmonic acid signaling pathways, while sustained ABA biosynthesis was an adaptive trait under neutral salinity. Exploring the genes with non-shared expression trends between salinity types, we identified sequence variation at the BGAL4 locus associated with advantageous responses to each type of salinity. Weighted correlation network analysis (WGCNA) validated the significant involvement of gene co-expression modules targeted by the enrichment analyses, highlighting the hubs correlated with favorable responses to both salinity types. Overall, the present study points out the complex physiological and genetic mechanisms responsible for plant tolerance to alkaline salinity and proposes target genes for breeding strategies under alkaline saline soils.

A large structural variant collection in Holstein cattle and associated database for variant discovery, characterization, and application

BackgroundStructural variants (SVs) such as deletions, duplications, and insertions are known to contribute to phenotypic variation but remain challenging to identify and genotype. A more complete, accessible, and assessable collection of SVs will assist efforts to study SV function in cattle and to incorporate SV genotyping into animal evaluation.ResultsIn this work we produced a large and deeply characterized collection of SVs in Holstein cattle using two popular SV callers (Manta and Smoove) and publicly available Illumina whole-genome sequence (WGS) read sets from 310 samples (290 male, 20 female, mean 20X coverage). Manta and Smoove identified 31 K and 68 K SVs, respectively. In total the SVs cover 5% (Manta) and 6% (Smoove) of the reference genome, in contrast to the 1% impacted by SNPs and indels. SV genotypes from each caller were confirmed to accurately recapitulate animal relationships estimated using WGS SNP genotypes from the same dataset, with Manta genotypes outperforming Smoove, and deletions outperforming duplications. To support efforts to link the SVs to phenotypic variation, overlapping and tag SNPs were identified for each SV, using genotype sets extracted from the WGS results corresponding to two bovine SNP chips (BovineSNP50 and BovineHD). 9% (Manta) and 11% (Smoove) of the SVs were found to have overlapping BovineHD panel SNPs, while 21% (Manta) and 9% (Smoove) have BovineHD panel tag SNPs. A custom interactive database (https://svdb-dc.pslab.ca) containing the identified sequence variants with extensive annotations, gene feature information, and BAM file content for all SVs was created to enable the evaluation and prioritization of SVs for further study. Illustrative examples involving the genes POPDC3, ORM1, G2E3, FANCI, TFB1M, FOXC2, N4BP2, GSTA3, and COPA show how this resource can be used to find well-supported genic SVs, determine SV breakpoints, design genotyping approaches, and identify processed pseudogenes masquerading as deletions.ConclusionsThe resources developed through this study can be used to explore sequence variation in Holstein cattle and to develop strategies for studying SVs of interest. The lack of overlapping and tag SNPs from commonly used SNP chips for most of the SVs suggests that other genotyping approaches will be needed (for example direct genotyping) to understand their potential contributions to phenotype. The included SV genotype assessments point to challenges in characterizing SVs, especially duplications, using short-read data and support ongoing efforts to better characterize cattle genomes through long-read sequencing. Lastly, the identification of previously known functional SVs and additional CDS-overlapping SVs supports the phenotypic relevance of this dataset.

Large TRAPPC11 gene deletions as a cause of muscular dystrophy and their estimated genesis

BackgroundTransport protein particle (TRAPP) is a multiprotein complex that functions in localising proteins to the Golgi compartment. The TRAPPC11 subunit has been implicated in diseases affecting muscle, brain, eye and...

Investigation of the Putative Functional Relevance of the IL-6 3’UTR Genetic Variants with Athletic Phenotype in Turkish Triathletes

Background/aim: Previous research suggests that genetic variants in the IL-6 gene contribute to sport-related traits and athletic performance. We aimed to identify sequence variants in the IL-6 gene region comprising the 3' untranslated region (UTR) in the Turkish triathletes and sedentary individuals and assessed their putative roles in tendency to athletic phenotype. Materials and methods: Sequence variants were identified in the Turkish triathletes (n=47) and sedentary individuals (n=46) by Sanger sequencing. Allele/genotype frequencies and linkage disequilibrium (LD) patterns were calculated by the Haploview program. The functional significance of the detected variants was analyzed using in-silico prediction tools. Results: Four single nucleotide variants (rs13306435, rs747302620, rs2069849, rs13306436) were detected in the total sample by sequencing the target region. Notably, rs13306436-3'UTR/IL-6 was only seen in the triathletes, while the exonic rs747302620 was observed in only sedentary group. Also, rs13306436G>A causes loss/gain sites for binding multiple miRNAs that may be associated with athletic performance. Conclusion: Our findings indicate that the 3'UTR/IL-6 may have functional relevance in determining sports talent. Future comprehensive studies focusing on the IL-6 gene in athletes may pave the way for not only determining the athletic status of the individuals but also have implications for translational medicine.

Whole Exome Sequencing Revealing a Novel PBX1 Gene Variant in a Chinese Family Causing Recurrent Neonatal Death.

Causative mutations of PBX1 are associated with congenital abnormalities of the kidney and urinary tract (CAKUT), often accompanied by hearing loss, abnormal ear morphology, or developmental delay. The aim of the present investigation was to introduce a novel variant in the PBX1 gene identified in a Chinese family, leading to recurrent neonatal mortality. A pregnant woman (gravida 5, para 0), who had experienced recurrent neonatal deaths, sought genetic etiology diagnosis. Whole exome sequencing (WES) was conducted to identify sequence variants and copy number variants in the fetus presenting with posterior nuchal cystic hygroma and fetal hydrops. A novel NM_002585.4:c.694G>C(p.D232H) in PBX1 was identified in the fetus through trio whole exome sequencing (WES), revealing a paternal mosaic PBX1 variant in blood at 11.54% (6/52 variants reads). Subsequent parental Sanger sequencing confirmed the variant detected by WES. Ultimately, the variant was classified as likely pathogenic, leading the family to elect pregnancy termination at 17 weeks gestation. The novel variant in the PBX1 gene appears to be a significant factor contributing to recurrent neonatal deaths in the Chinese family. Such findings expand the spectrum of PBX1 gene variants and provide valuable perinatal guidance for diagnosing fetuses with PBX1 mutations.

Knockout mice with pituitary malformations help identify human cases of hypopituitarism

BackgroundCongenital hypopituitarism (CH) and its associated syndromes, septo-optic dysplasia (SOD) and holoprosencephaly (HPE), are midline defects that cause significant morbidity for affected people. Variants in 67 genes are associated with CH, but a vast majority of CH cases lack a genetic diagnosis. Whole exome and whole genome sequencing of CH patients identifies sequence variants in genes known to cause CH, and in new candidate genes, but many of these are variants of uncertain significance (VUS).MethodsThe International Mouse Phenotyping Consortium (IMPC) is an effort to establish gene function by knocking-out all genes in the mouse genome and generating corresponding phenotype data. We used mouse embryonic imaging data generated by the Deciphering Mechanisms of Developmental Disorders (DMDD) project to screen 209 embryonic lethal and sub-viable knockout mouse lines for pituitary malformations.ResultsOf the 209 knockout mouse lines, we identified 51 that have embryonic pituitary malformations. These genes not only represent new candidates for CH, but also reveal new molecular pathways not previously associated with pituitary organogenesis. We used this list of candidate genes to mine whole exome sequencing data of a cohort of patients with CH, and we identified variants in two unrelated cases for two genes, MORC2 and SETD5, with CH and other syndromic features.ConclusionsThe screening and analysis of IMPC phenotyping data provide proof-of-principle that recessive lethal mouse mutants generated by the knockout mouse project are an excellent source of candidate genes for congenital hypopituitarism in children.

Genetic variations of Toll-like receptor 4 gene in exon 2 of South African Dorper sheep.

The study was conducted to identify the sequence variation of Toll-like receptor 4 (TLR4) in exon 2 of South African Dorper sheep. Blood samples were collected from fifty (n = 50) South African Dorper sheep aged between 3 and 4 years. The Deoxyribonucleic acid (DNA) was extracted, amplified, and sequenced for the TLR4 gene. DNA sequencing was used to identify the sequence variations of the TLR4 gene in South African Dorper sheep. The results showed that one synonymous single nucleotide polymorphism (SNP) of the TLR4 gene in exon 2 position T2249C was identified. Two genotypes (TT and TC) were discovered from the identified SNP. The dominant genotype was TT (0.60) over TC (0.40), with the dominant allele T (0.80) over C (0.20). The results also indicated that the used population was in the Hady-Weinberg Equilibrium. Polymorphism genetic analysis findings suggest that the identified sequence variation of TLR4 in exon 2 of South African Dorper sheep was moderate polymorphism. TLR4 gene at exon 2 of South African Dorper sheep had the SNP (T>C) at position 2249 bp with two genotypes (TT and TC).

Sequence optimized diagnostic assay for Ebola virus detection

Rapid pathogen identification is a critical first step in patient isolation, treatment, and controlling an outbreak. Real-time PCR is a highly sensitive and specific approach commonly used for infectious disease diagnostics. However, mismatches in the primer or probe sequence and the target organism can cause decreased sensitivity, assay failure, and false negative results. Limited genomic sequences for rare pathogens such as Ebola virus (EBOV) can negatively impact assay performance due to undiscovered genetic diversity. We previously developed and validated several EBOV assays prior to the 2013–2016 EBOV outbreak in West Africa, and sequencing EBOV Makona identified sequence variants that could impact assay performance. Here, we assessed the impact sequence mismatches have on EBOV assay performance, finding one or two primer or probe mismatches resulted in a range of impact from minimal to almost two log sensitivity reduction. Redesigning this assay improved detection of all EBOV variants tested. Comparing the performance of the new assay with the previous assays across a panel of human EBOV samples confirmed increased assay sensitivity as reflected in decreased Cq values with detection of three positive that tested negative with the original assay.

Survivin Expression in Luminal Breast Cancer and Adjacent Normal Tissue for Immuno-Oncology Applications.

Survivin (BIRC5) is a tumor-associated antigen (TAA) overexpressed in various tumors but present at low to undetectable levels in normal tissue. Survivin is known to have a high expression in breast cancer (e.g., Ductal Carcinoma in situ (DCIS) and triple negative breast cancer). Previous studies have not compared survivin expression levels in DCIS tumor samples to levels in adjacent, normal breast tissue from the same patient. To ensure the effective use of survivin as a target for T cell immunotherapy of breast cancer, it is essential to ascertain the varying levels of survivin expression between DCIS tumor tissue samples and the adjacent normal breast tissue taken from the same patient simultaneously. Next-generation sequencing of RNA (RNA-seq) in normal breast tissue and tumor breast tissue from five women presenting with DCIS for lumpectomy was used to identify sequence variation and expression levels of survivin. The identity of both tumor and adjacent normal tissue samples were corroborated by histopathology. Survivin was overexpressed in human breast tissue tumor samples relative to the corresponding adjacent human normal breast tissue. Wild-type survivin transcripts were the predominant species identified in all tumor tissue sequenced. This study demonstrates upregulated expression of wild type survivin in DCIS tumor tissue versus normal breast tissue taken from the same patient at the same time, and provides evidence that developing selective cytotoxic T lymphocyte (CTL) immunotherapy for DCIS targeting survivin warrants further study.

Sequence variant affects GCSAML splicing, mast cell specific proteins, and risk of urticaria

Urticaria is a skin disorder characterized by outbreaks of raised pruritic wheals. In order to identify sequence variants associated with urticaria, we performed a meta-analysis of genome-wide association studies for urticaria with a total of 40,694 cases and 1,230,001 controls from Iceland, the UK, Finland, and Japan. We also performed transcriptome- and proteome-wide analyses in Iceland and the UK. We found nine sequence variants at nine loci associating with urticaria. The variants are at genes participating in type 2 immune responses and/or mast cell biology (CBLB, FCER1A, GCSAML, STAT6, TPSD1, ZFPM1), the innate immunity (C4), and NF-κB signaling. The most significant association was observed for the splice-donor variant rs56043070[A] (hg38: chr1:247556467) in GCSAML (MAF = 6.6%, OR = 1.24 (95%CI: 1.20–1.28), P-value = 3.6 × 10-44). We assessed the effects of the variants on transcripts, and levels of proteins relevant to urticaria pathophysiology. Our results emphasize the role of type 2 immune response and mast cell activation in the pathogenesis of urticaria. Our findings may point to an IgE-independent urticaria pathway that could help address unmet clinical need.

P53 Dysregulation in Breast Cancer: Insights on Mutations in the TP53 Network and p53 Isoform Expression.

In breast cancer, p53 expression levels are better predictors of outcome and chemotherapy response than TP53 mutation. Several molecular mechanisms that modulate p53 levels and functions, including p53 isoform expression, have been described, and may contribute to deregulated p53 activities and worse cancer outcomes. In this study, TP53 and regulators of the p53 pathway were sequenced by targeted next-generation sequencing in a cohort of 137 invasive ductal carcinomas and associations between the identified sequence variants, and p53 and p53 isoform expression were explored. The results demonstrate significant variability in levels of p53 isoform expression and TP53 variant types among tumours. We have shown that TP53 truncating and missense mutations modulate p53 levels. Further, intronic mutations, particularly polymorphisms in intron 4, which can affect the translation from the internal TP53 promoter, were associated with increased Δ133p53 levels. Differential expression of p53 and p53 isoforms was associated with the enrichment of sequence variants in p53 interactors BRCA1, PALB2, and CHEK2. Taken together, these results underpin the complexity of p53 and p53 isoform regulation. Furthermore, given the growing evidence associating dysregulated levels of p53 isoforms with cancer progression, certain TP53 sequence variants that show strong links to p53 isoform expression may advance the field of prognostic biomarker study in breast cancer.

Novel mechanisms of macrolide resistance revealed by in vitro selection and genome analysis in Mycoplasma pneumoniae.

Mycoplasma pneumoniae is an important pathogen causing upper and lower respiratory tract infections in children and other age groups. Macrolides are the recommended treatments of choice for M. pneumoniae infections. However, macrolide resistance in M. pneumoniae is increasing worldwide, which complicates the treatment strategies. The mechanisms of macrolide resistance have been extensively studied focusing on the mutations in 23S rRNA and ribosomal proteins. Since the secondary treatment choice for pediatric patients is very limited, we decided to look for potential new treatment strategies in macrolide drugs and investigate possible new mechanisms of resistance. We performed an in vitro selection of mutants resistant to five macrolides (erythromycin, roxithromycin, azithromycin, josamycin, and midecamycin) by inducing the parent M. pneumoniae strain M129 with increasing concentrations of the drugs. The evolving cultures in every passage were tested for their antimicrobial susceptibilities to eight drugs and mutations known to be associated with macrolide resistance by PCR and sequencing. The final selected mutants were also analyzed by whole-genome sequencing. Results showed that roxithromycin is the drug that most easily induces resistance (at 0.25 mg/L, with two passages, 23 days), while with midecamycin it is most difficult (at 5.12 mg/L, with seven passages, 87 days). Point mutations C2617A/T, A2063G, or A2064C in domain V of 23S rRNA were detected in mutants resistant to the 14- and 15-membered macrolides, while A2067G/C was selected for the 16-membered macrolides. Single amino acid changes (G72R, G72V) in ribosomal protein L4 emerged during the induction by midecamycin. Genome sequencing identified sequence variations in dnaK, rpoC, glpK, MPN449, and in one of the hsdS (MPN365) genes in the mutants. Mutants induced by the 14- or 15-membered macrolides were resistant to all macrolides, while those induced by the 16-membered macrolides (midecamycin and josamycin) remained susceptible to the 14- and 15-membered macrolides. In summary, these data demonstrated that midecamycin is less potent in inducing resistance than other macrolides, and the induced resistance is restrained to the 16-membered macrolides, suggesting a potential benefit of using midecamycin as a first treatment choice if the strain is susceptible.

An RNA-based system to study hepatitis B virus replication and evaluate antivirals.

Hepatitis B virus (HBV) chronically infects an estimated 300 million people, and standard treatments are rarely curative. Infection increases the risk of liver cirrhosis and hepatocellular carcinoma, and consequently, nearly 1 million people die each year from chronic hepatitis B.Tools and approaches that bring insights into HBV biology and facilitate the discovery and evaluation of antiviral drugs are in demand. Here, we describe a method to initiate the replication of HBV, a DNA virus, using synthetic RNA. This approach eliminates contaminating background signals from input virus or plasmid DNA that plagues existing systems and can be used to study multiple stages of HBV replication. We further demonstrate that this method can be uniquely applied to identify sequence variants that confer resistance to antiviral drugs.

A Highly Efficient Workflow for Detecting and Identifying Sequence Variants in Therapeutic Proteins with a High Resolution LC-MS/MS Method.

Large molecule protein therapeutics have steadily grown and now represent a significant portion of the overall pharmaceutical market. These complex therapies are commonly manufactured using cell culture technology. Sequence variants (SVs) are undesired minor variants that may arise from the cell culture biomanufacturing process that can potentially affect the safety and efficacy of a protein therapeutic. SVs have unintended amino acid substitutions and can come from genetic mutations or translation errors. These SVs can either be detected using genetic screening methods or by mass spectrometry (MS). Recent advances in Next-generation Sequencing (NGS) technology have made genetic testing cheaper, faster, and more convenient compared to time-consuming low-resolution tandem MS and Mascot Error Tolerant Search (ETS)-based workflows which often require ~6 to 8 weeks data turnaround time. However, NGS still cannot detect non-genetic derived SVs while MS analysis can do both. Here, we report a highly efficient Sequence Variant Analysis (SVA) workflow using high-resolution MS and tandem mass spectrometry combined with improved software to greatly reduce the time and resource cost associated with MS SVA workflows. Method development was performed to optimize the high-resolution tandem MS and software score cutoff for both SV identification and quantitation. We discovered that a feature of the Fusion Lumos caused significant relative under-quantitation of low-level peptides and turned it off. A comparison of common Orbitrap platforms showed that similar quantitation values were obtained on a spiked-in sample. With this new workflow, the amount of false positive SVs was decreased by up to 93%, and SVA turnaround time by LC-MS/MS was shortened to 2 weeks, comparable to NGS analysis speed and making LC-MS/MS the top choice for SVA workflow.

The Association between Genetic Variants and Gene Expression in RAAS Genes Using Captive-Bred Vervet Monkeys (Chlorocebus aethiops)

Mendelian genetics contribute largely to the development of hypertension; therefore, the identification of genetic variants related to blood pressure (BP) regulation remains crucial and may reveal new therapeutic drug targets. The purpose of the present study was to screen the captive-bred Vervet colony for salt-sensitive sequence variants or single nucleotide polymorphisms (SNPs) in the selected Renin-Angiotensin-Aldosterone System (RAAS) genes associated with salt sensitivity. Blood samples were collected from 16 captive-bred Vervet monkeys for genotyping and gene expression analysis. The impact of the identified sequence variants was determined using online prediction tools. Sanger sequencing analysis revealed 21 sequence variants in AGT, CYP3A5, GRK4, and SCL4A5, of which 19 were novel and two were previously reported in humans. All novel variants were either predicted to be polymorphic, disease-causing, or possibly damaging by prediction tools. Furthermore, the mRNA expression for AGT was significantly higher in the normal BP group ( p value = 0.02), and a similar trend was observed for CYP3A5 and GRK4, whereas SCL4A5 was higher in the hypertensive group. The identified salt-sensitive variants specifically in GRK4 may be suggestive to be the attributing factor of the elevated BP levels in these captive-bred Vervet monkeys. Therefore, RAAS variants could be considered as a biomarker to identify the potential risk of developing hypertension in both humans and nonhuman primates.

Biallelic mutations in FLG, TGM1, and STS genes segregated with different types of ichthyoses in eight families of Pakistani origin.

Congenital ichthyosis is a diverse group of keratinization disorders associated with generalized scaling of skin of varying severity. The non-syndromic forms of congenital ichthyosis are further grouped into common ichthyosis (ichthyosis vulgaris and X-linked ichthyosis), autosomal recessive congenital ichthyosis, and keratopathic ichthyosis. To identify sequence variants involved in different forms of hereditary ichthyoses. We studied eight families with different types of ichthyosis including four families with autosomal recessive congenital ichthyosis and four families with common ichthyosis. Whole exome sequencing and PCR based genotyping was carried out to find out the molecular basis of disease. In one family, a novel duplication sequence variant NM_002016.2:c.2767dupT; NP_002007.1:p.Ser923PhefsTer2 was identified in FLG gene; in four families a previously reported nonsense sequence variant NM_000359.3:c.232C>T; NP_002007.1:p.Arg78Ter was identified in TGM1 gene, while, in three families of X-linked recessive ichthyosis, the whole STS gene (NM_001320752.2; NP_001307681.2) regions were deleted. Gene expression studies have not been performed that would have strengthened the findings of computational analysis. This study highlights the significance of the c.232C>T variant in the TGM1 gene as a possible founder mutation, complete STS gene deletion as reported previously in Pakistani population, while novel sequence variant in the FLG gene expands the spectrum of variations in this gene. These findings may be used for genetic counseling of the studied families.

Karyopherin α deficiency contributes to human preimplantation embryo arrest

Preimplantation embryo arrest (PREMBA) is a common cause of female infertility and recurrent failure of assisted reproductive technology. However, the genetic basis of PREMBA is largely unrevealed. Here, using whole-exome sequencing data from 606 women experiencing PREMBA compared with 2,813 controls, we performed a population and gene-based burden test and identified a candidate gene, karyopherin subunit α7 (KPNA7). In vitro studies showed that identified sequence variants reduced KPNA7 protein levels, impaired KPNA7 capacity for binding to its substrate ribosomal L1 domain-containing protein 1 (RSL1D1), and affected KPNA7 nuclear transport activity. Comparison between humans and mice suggested that mouse KPNA2, rather than mouse KPNA7, acts as an essential karyopherin in embryonic development. Kpna2-/- female mice showed embryo arrest due to zygotic genome activation defects, recapitulating the phenotype of human PREMBA. In addition, female mice with an oocyte-specific knockout of Rsl1d1 recapitulated the phenotype of Kpna2-/- mice, demonstrating the vital role of substrate RSL1D1. Finally, complementary RNA (cRNA) microinjection of human KPNA7, but not mouse Kpna7, was able to rescue the embryo arrest phenotype in Kpna2-/- mice, suggesting mouse KPNA2 might be a homologue of human KPNA7. Our findings uncovered a mechanistic understanding for the pathogenesis of PREMBA, which acts by impairing nuclear protein transport, and provide a diagnostic marker for PREMBA patients.