家蚕CyPA基因的克隆、表达谱及进化分析

CyP蛋白家族在蛋白质折叠过程中起着重要作用。本研究克隆了家蚕Bombyx mori CyPA基因(BmCyPA)，该基因由2个外显子和1个内含子组成，推导开放阅读框编码165个氨基酸，分子量为19.4 kD，等电点为8.79。序列分析表明BmCyPA在不同物种间具有高度的保守性，含有肽酰脯氨酸顺反异构酶活性位点及与CsA侧链结合的氨基酸，提示BmCyPA可能具有肽酰脯氨酸顺反异构酶活性和与CsA结合的特性。组织表达谱及EST数据分析显示，BmCyPA在丝腺中高丰度表达。通过对不同物种来源的CyP基因的进化分析，进一步预测了BmCyP基因的功能，BmCyP可能与丝蛋白的正确折叠相关。

Cloning, expression pattern and phylogenetic analysis of cyclophilin A gene in the silkworm, Bombyx mori

CyP protein family plays an important role in the process of protein folding. In this study, a novel silkworm gene BmCyPA was cloned, which comprises 2 exons and 1 intron. The deduced BmCyPA protein contains 165 amino acids, its molecular mass is 19.4 kD and pI is 8.79. Sequences analysis showed that BmCyPA is highly conserved among different species. The BmCyPA protein has peptidylprolyl cis-trans-isomerase active sites and contains specific amino acids which can bind to the side chain of CsA, which indicated that BmCyPA has potential cis-trans-isomerase activtity and can combine with CsA. RT-PCR of tissue expression pattern and EST analysis revealed that BmCyPA is specifically and highly expressed in silk gland. The potential function of BmCyPA gene was further analyzed by phylogenetic analysis of CyPA genes from different species. The results suggest that BmCyP may be involved in the process of fibroin folding.