Deleterious Nonsynonymous SNP Found within <i>HLA-DRB1</i>Gene Involved in Allograft Rejection in Sudanese Family: Using DNA Sequencing and Bioinformatics Methods

Renal transplantation provides the best long-term treatment for chronic renal failure. Single-nucleotide polymorphisms (SNPs) play a major role in the understanding of the genetic basis of many complex human diseases. Also, the genetics of human phenotype variation could be understood by knowing the functions of these SNPs. It is still a major challenge to identify the functional SNPs in a disease-related gene. This work explored how SNPs mutations in HLA-DRB1 gene could affect renal transplantation rejection. This study was carried out in Ahmed Gasim Hospital, Renal Dialysis Center during the period, from September 2012 to November 2013. Blood samples from five Sudanese patients (different families) with known renal transplantation rejection were collected before hemodialysis, furthermore one blood sample for control. DNA sequences results and detected SNPs were analyzed using bioinformatics tools (BLAST, SIFT, nsSNP Analyzer, PolyPhen, I-mutant, BioEdit, CPH, Chimera, Box shade and Project Hope). In addition, international databases were used for datasets [NCBI, Uniprot]. Results showed that, three SNPs were detected;two of three SNPs were predicted as tolerant or benign (rs1059575, novel) and one was deleterious (rs17885437). This study concluded that the identification of pathological SNPs could be an answer to unknown causes for a lot of organ transplantation rejection cases.

A systematic survey of LU domain-containing proteins reveals a novel human gene,LY6A,which encodes the candidate ortholog of mouse Ly-6A/Sca-1 and is aberrantly expressed in pituitary tumors

The Ly-6 and uPAR(LU)domain-containing proteins represent a large family of cell-surface markers.In particular,mouse Ly-6A/Sca-1 is a widely used marker for various stem cells;however,its human ortholog is missing.In this study,based on a systematic survey and comparative genomic study of mouse and human LU domain-containing proteins,we identified a previously unannotated human gene encoding the candidate ortholog of mouse Ly-6A/Sca-1.This gene,hereby named LY6A,reversely overlaps with a lncRNA gene in the majority of exonic sequences.We found that LY6A is aberrantly expressed in pituitary tumors,but not in normal pituitary tissues,and may contribute to tumorigenesis.Similar to mouse Ly-6A/Sca-1,human LY6A is also upregulated by interferon,suggesting a conserved transcriptional regulatory mechanism between humans and mice.We cloned the full-length LY6A cDNA,whose encoded protein sequence,domain architecture,and exon‒intron structures are all well conserved with mouse Ly-6A/Sca-1.Ectopic expression of the LY6A protein in cells demonstrates that it acts the same as mouse Ly-6A/Sca-1 in their processing and glycosylphosphatidylinositol anchoring to the cell membrane.Collectively,these studies unveil a novel human gene encoding a candidate biomarker and provide an interesting model gene for studying gene regulatory and evolutionary mechanisms.

Evaluation of Six Methods for Estimating Synonymous and Non-synonymous Substitution Rates

Methods for estimating synonymous and nonsynonymous substitution rates among protein-coding sequences adopt different mutation (substitution) models with subtle yet significant differences, which lead to different estimates of evolutionary information. Little attention has been devoted to the comparison of methods for obtaining reliable estimates since the amount of sequence variations within targeted datasets is always unpredictable. To our knowledge, there is little information available in literature about evaluation of these different methods. In this study, we compared six widely used methods and provided with evaluation results using simulated sequences. The results indicate that incorporating sequence features (such as transition/transversion bias and nucleotide/codon frequency bias) into methods could yield better performance. We recommend that conclusions related to or derived from Ka and Ks analyses should not be readily drawn only according to results from one method.