Objective: To clone a novel diabetic angiopathy related protein gene-C5orf21 and study its roles in diabetic macroangiopathy.
Methods: The open reading frame (ORF) of C5orf21 gene was cloned into vector from human aortic tissues by a RT-PCR-based approach and identified by enzyme-cutting and sequencing. The structure and function of C5orf21 gene and protein were further analyzed by bioinformatics technology. The mRNA expression of C5orf21 gene in human tissues and in vascular cells was analyzed by RT-PCR. RT-PCR was used to observe the effect of high glucose, low-density lipoprotein (LDL) and free fatty acid (FFA) upon the expression of C5orf21 gene in macrophages.
Results: C5orf21 gene was successfully inserted into pDrive vector and identified for the first time at the level of mRNA. There are five C5orf21 gene splice variants in human aortic tissue and their length of ORF are 1251, 1113, 894, 810 and 810 bp respectively. Two kinds of splice variants have yet to be included in GenBank database. Two kinds of splice variants have the same ORF and their differences are mainly in the bases in the 5' untranslated region. Bioinformatics analysis found that C5orf21 gene was located in chromosome 5q15 and C5orf21 protein contained Arb2 domain associated with histone H3 lysine 9 methylation. C5orf21 gene was normally expressed in many tissues. Fat and aortic tissues had the highest expression. The expression of C5orf21 gene could be detected in human aortic endothelial cell, aortic smooth muscle cell and macrophages. High glucose, LDL and FFA (esp.high glucose) up-regulated the expression of C5orf21 gene in macrophage.
Conclusion: C5orf21 gene contains five splice variants and it is identified for the first time at the level of mRNA. The changes of C5orf21 gene expression are correlated with diabetic macroangiopathy.