大鼠不同发育阶段β-防御素-2基因在肺组织的表达研究

Study of β-defensin rBD-2 gene expression in the pulmonary tissues of the fetal, neonatal and adult rats

目的 :探讨大鼠 β -防御素 - 2基因在肺组织表达的发育调控。方法 :根据Genbank大鼠 β -防御素- 2的cDNA序列 ,设计一对特异引物。采用RT -PCR技术在大鼠不同发育阶段的肺组织总RNA中 ,扩增其特异cDNA片段 ,并进行DNA序列测定。借助Genbank中BLAST程序 ,将从该cDNA序列推导的氨基酸序列与人的hBD -2和大鼠的rBD - 1做相似性分析。结果 :从足月胎鼠、出生 8h和 4d以及成年大鼠相同重量肺组织所提取的总RNA中 ,均扩增出一条密度相同、长度约为 2 2 0bp的cDNA片段。在所推导氨基酸序列中与hBD - 2氨基酸相同率为48 6 % (17/ 35 ) ,与rBD - 1氨基酸残基的相同率为 31% (11/ 35 )。其成熟分子链长 35个氨基酸残基 ,含 β -防御素共有的且排列次序相同的 6个典型的半胱氨酸和其它保守氨基酸残基。结论 :本实验表明不同发育阶段大鼠肺组织均表达β - 防御素 - 2mRNA 。

AIM: To investigate the developmental regulation of β-defensin rBD-2 gene expression in the rat lung. METHOD: Total RNA was isolated from the pulmonary tissues of the fetal, neonatal and adult rats. RT-PCR were performed with primers (P 1: TTCAGTCATGAGGATCCATT AC; P 2: TGGAACTTGGTCTTTTTATCTAC). The RT-PCR products were cloned into pGEM-T easy vector and the recombinant plasmid was analyzed with EcoR1 digestion and the inserted DNA sequencing was performed on ABI PRISM-377 DNA sequencer. RESULTS: Rat β-defensin-2 transcripts were detected in all the pulmonary tissues of rats during different developmental stages, e.g. at just before birth, 8 hours and 4 days after birth , and adult. CONCLUSION: The rat β-defensin-2 is constitutively expressed in the pulmonary tissues, suggesting that β-defensin-2 may play a role in the lung innate defense against infection.