Expression analysis of Tsga10 during in vitro differentiation of germ cells from mouse embryonic stem cell

Background: About 15% of couples have fertility problems and male factor in fertility accounts for half of the cases. In vitro generation of germ cells introduces a novel approach to male infertility and provides an effective system in gene tracking studies, however many aspects of this process have remained unclear. We aimed to promote mouse embryonic stem cells (mESCs) differentiation into germ cells and evaluate its effectiveness with tracking the expression of the Testis specific 10 (Tsga10) during this process. Methods: This is an in vitro study that was performed in department of Medical Genetics in Tehran University of Medical Sciences from February 2012 to March 2013. Mouse embryonic stem cells were cultured on mouse embryonic fibroblast as feeder layer. Then mESCs were differentiated into germ cells in the presence of Retinoic Acid. Based on developmental schedule of the postnatal testis, samples were taken on the 7th, 12th and 25th days of the culture and were subjected to expression analysis of a panel of germ cell specific genes (Stra8 as pre-meiotic, Dazl and Sycp3‌ as meiotic and Protamin1 and Spata19 as Post-meiotic). Expression of Testis Specific Gene 10 (Tsga10) at RNA and protein levels was then analyzed. Results: It was shown that transition of embryonic stem cells from mitosis to meiosis occurred between 7th and 12th days of mESC culture and post-meiotic gene expression did not occur until 25th day of the culture. Results showed low level of Tsga10 expression in undifferentiated stem cells. During transition from meiotic to post-meiotic phase, Tsga10 expression increased in 6.6 folds. This finding is in concordance with in vivo changes during transition from pre-pubertal to pubertal stage. Localization of processed and unprocessed form of the related protein was similar to those in vivo as well. Conclusion: Expression pattern of Tsga10, as a gene with critical function in spermatogenesis, is similar during in vitro and in vivo germ cell generation. The results suggest that in vitro derived germ cells could be a trusted model to study genes behavior during spermatogenesis

Identification of a novel mutation in the ST14 gene in an Iranian family with ichthyosis and hypotrichosis

Inherited ichthyosis is a heterogeneous group of rare cutaneous disorders characterized by hyperkeratosis and scaly skin. So far, only a few genetic studies on ichthyosis have been performed in Iran. Herein, we reported a family with two cases of ichthyosis and hypotrichosis that were investigated by whole exome sequencing. Targeted data analysis identified a novel nonsense variant c.1243C>T (p.Gln415Ter) located at exon 11 of the ST14 gene in the proband. Sanger sequencing showed co-segregation of this mutation with the disease in this family. Further studies are needed to develop knowledge about the spectrum of changes in this gene and their effects on protein function and disease phenotype

Identification of a novel mutation in the ST14 gene in an Iranian family with ichthyosis and hypotrichosis

Inherited ichthyosis is a heterogeneous group of rare cutaneous disorders characterized by hyperkeratosis and scaly skin. So far, only a few genetic studies on ichthyosis have been performed in Iran. Herein, we reported a family with two cases of ichthyosis and hypotrichosis that were investigated by whole exome sequencing. Targeted data analysis identified a novel nonsense variant c.1243C>T (p.Gln415Ter) located at exon 11 of the ST14 gene in the proband. Sanger sequencing showed co-segregation of this mutation with the disease in this family. Further studies are needed to develop knowledge about the spectrum of changes in this gene and their effects on protein function and disease phenotype

An Efficient Trio-Based Mini-Haplotyping Method for Genetic Diagnosis of Phenylketonuria

Objective The phenylalanine hydroxylase (PAH) locus has high linkage disequilibrium. Haplotypes related to this locus may thus be considered sufficiently informative for genetic diagnosis and carrier screening using multi-allelic markers. In this study, we present an efficient method for haplotype analysis of PAH locus using multiplexing dyes. In addition, we explain how to resolve the dye shift challenge in multiplex short tandem repeat (STR) genotyping. Materials and Methods One hundred family trios were included in this descriptive study. The forward primer of a tetra-nucleotide STR and the reverse primer of a variable number tandem repeat (VNTR) were labeled with three different non-overlapping dyes 5-carboxyfluorescein (FAM), 6-carboxy-N,N,N’,N’-tetramethylrhodamine (HEX) and 6-carboxy-N,N,N’,N’-tetramethylrhodamine (TAMRA). The polymerase chain reaction (PCR) products from each family trio were multiplexed for capillary electrophoresis and results were analyzed using Peak Scanner software. Results Multiplexing trio products decreased the cost significantly. The TAMRA labeled products had a significant predictable shift (migrated at a slower electrophoretic rate) relative to the HEX and FAM labeled products. Through our methodology we achieve, the less inter-dye shift than intra-dye shift variance. Correcting the dye shift in the labeled products, according to the reference allele size, significantly decreased the inter-dye variability (P<0.001). Conclusion Multiplexing trio products helps to detect and resolve the dye shift accurately in each family, which otherwise would result in diagnostic error. The dye system of FAM, HEX and TAMRA is more feasible and cheaper than other dye systems