Wang L Q, Baldwin R L, Jesse B W
Department of Animal Science, Rutgers, State University of New Jersey, New Brunswick 08903, USA.
J Anim Sci. 1996 Feb;74(2):345-53. doi: 10.2527/1996.742345x.
To identify genes involved in the postnatal development of sheep ruminal epithelium, a lambda gt22a cDNA library was constructed from poly(A)+ RNA isolated from mature sheep ruminal epithelium. A plus/minus screening procedure was used to identify genes expressed in mature but not in neonatal ruminal epithelium. One of the cDNA clones isolated encodes an ovine carbonic anhydrase, based on nucleotide and deduced peptide sequence analysis. The deduced peptide is most closely related to eukaryotic type I carbonic anhydrase, based on comparison with all available carbonic anhydrase sequences. Northern blot hybridization confirmed that the amount of mRNA complementary to the carbonic anhydrase cDNA clone is more than five times higher in ruminal epithelium for mature sheep (12 wk old) than in ruminal epithelium from neonatal lambs (< 12h old). Messenger RNA complementary to this cDNA clone was found only in the epithelium of the ruminant forestomach compartments (i.e., rumen, reticulum, and omasum), but small amounts of hybridizable mRNA were also found in sheep skin. This carbonic anhydrase cDNA clone will allow the study of transcriptional regulation of the carbonic anhydrase gene during ruminal epithelial development.
为了鉴定参与绵羊瘤胃上皮产后发育的基因，从成熟绵羊瘤胃上皮分离的聚腺苷酸加尾RNA构建了λgt22a cDNA文库。采用正负筛选程序来鉴定在成熟而非新生瘤胃上皮中表达的基因。根据核苷酸和推导的肽序列分析，分离得到的一个cDNA克隆编码一种绵羊碳酸酐酶。与所有可用的碳酸酐酶序列比较表明，推导的肽与真核I型碳酸酐酶关系最为密切。Northern印迹杂交证实，与碳酸酐酶cDNA克隆互补的mRNA量在成熟绵羊（12周龄）的瘤胃上皮中比新生羔羊（<12小时龄）的瘤胃上皮中高出五倍以上。与该cDNA克隆互补的信使RNA仅在反刍动物前胃区室（即瘤胃、网胃和瓣胃）的上皮中发现，但在绵羊皮肤中也发现了少量可杂交的mRNA。这个碳酸酐酶cDNA克隆将有助于研究瘤胃上皮发育过程中碳酸酐酶基因的转录调控。
