A novel splice mutation in EXT1 gene of hereditary multiple osteochondroma and analysis of its pathogenic mechanism / 中华检验医学杂志

Objective To analyse a novel splice mutation in EXT1 gene of hereditary multiple osteochondroma, and study its pathogenic mechanism.Methods In April of 2013, the proband was hospitalized from the outpatient department with multiple joint deformity for more than 20 years, peripheral blood of the proband and his parents were collected and genomic DNA was extracted .Coding regions and adjacent intron sequences of EXT1/EXT2 genes in genomic DNA of the family members were amplified and sequenced.Bioinformatics was used to analyze the mutation from sequencing .cDNA from peripheral blood of the proband ,the mother and normal control was made respectively as a template for amplifying coding regions of EXT1 gene, and the product was T-A cloned and sequenced.The abnormal transcripts of each group were counted and analyzed using chi square test to study the pathogenic mechanism of the mutation .Results Sequencing results of family members revealed that there was a heterozygous deletion mutation ( c.1284 +2del) in the 5′splice site of intron 4 in EXT1 gene of the proband and his mother .Bioinformatics predicted that exon 4 of EXT1 gene was skipping or spliced aberrantly due to the mutation .T-A clone and sequencing results as well as the statistical analysis suggested that there was a significantly higher proportion of transcripts with skipping exon 4 in the proband and his mother compared with the normal control (P=0.000, P<0.01).Conclusions c.1284+2del in EXT1 gene is reported for the first time internationally , which results in a considerable number of abnormal transcripts with skipping exon 4 in EXT1 gene, thereby influences the normal transcription and translation of EXT1 gene.

A novel mutation of c.2472+1G＞A in kit gene causes piebaldism in a Chinese family / 中华皮肤科杂志

Objective To make a molecular genetic analysis in a Chinese family with piebaldism,in order to find the causative mutation of this disease.Methods DNA and RNA were extracted from blood samples of the proband and other 13 members in this family.Ploymerase chain reaction (PCR),reverse transcription PCR and DNA sequencing were performed to detect the mutation of kit gene.Results A novel heterozygous mutation c.2472+1G>A in kit gene.which leads to the loss of 3' splicing site in exon 17 followed by the absence of exon 17,was found in all affected members,but not in an unaffected member in the family.Conclusion The novel mutation c.2472+1G>A may be associated with piebaldism initiation in this family.

Nucleosome Positioning and RNA Splicing / 生物化学与生物物理进展

Based on the characteristic of nucleotide distribution in nucleosome positioning and inhibiting sequences, the method of Increment of Diversity with Quadratic Discriminant (IDQD) was applied to the classification of these two types of sequences. The mean area under ROC curve archives 0.958. By using this model, the nucleosome formation potential was analyzed in the regions around the splice sites (GT/AG). The results show that coding regions have a high potential to form the nucleosome and the primary RNA transcripts are rigid, while DNA sequences corresponding to the splice sites and their adjacent intron regions tend to be nucleosome free and the primary transcripts from these regions are relative flexible. Moreover, the negative correlation between nucleosome positioning/inhibiting of DNA sequences and RNA flexibility/rigidity is demonstrated around the splice sites, providing a mechanism for understanding the correlation between the nucleosome positioning of DNA and the splicing of transcribed RNA sequences.