Tsuda T, Gallup M, Jany B, Gum J, Kim Y, Basbaum C
Department of Anatomy, University of California San Francisco.
Biochem Biophys Res Commun. 1993 Aug 31;195(1):363-73. doi: 10.1006/bbrc.1993.2052.
The purpose of this study was to isolate airway mucin cDNAs for use in studies of mucin biosynthesis in rat models of human airway disease. To this end, we screened a rat airway cDNA library with the human intestinal mucin cDNA SMUC 41 and obtained 7 positive clones. Preliminary characterization of each of these led us to focus on the clone expressing the 390 bp cDNA RAM 7s. Evidence indicating that RAM 7s encodes part of a rat airway mucin gene is that RAM 7s: (a) hybridizes in plaque lifts to SMUC 41, (b) hybridizes in Northern blots to large, polydisperse transcripts, (c) has a sequence encoding threonine-rich tandem repeats and (d) shows appropriate tissue-specific expression of cognate mRNA. The repetitive peptide encoded by RAM 7s includes five copies of the consensus sequence TTTTIITI. Because this sequence is different from those reported for two cDNAs previously isolated from rat intestinal libraries, we tentatively conclude that RAM 7s encodes part of a previously unidentified rat mucin gene.
本研究的目的是分离气道粘蛋白cDNA，用于人类气道疾病大鼠模型中粘蛋白生物合成的研究。为此，我们用人肠粘蛋白cDNA SMUC 41筛选大鼠气道cDNA文库，获得了7个阳性克隆。对这些克隆的初步鉴定使我们聚焦于表达390 bp cDNA RAM 7s的克隆。表明RAM 7s编码大鼠气道粘蛋白基因一部分的证据是：（a）在菌斑杂交中与SMUC 41杂交，（b）在Northern印迹中与大的、多分散的转录本杂交，（c）具有编码富含苏氨酸串联重复序列的序列，以及（d）显示同源mRNA有适当的组织特异性表达。RAM 7s编码的重复肽包括五个一致序列TTTTIITI拷贝。由于该序列与先前从大鼠肠道文库中分离的两个cDNA报道的序列不同，我们初步得出结论，RAM 7s编码一个先前未鉴定的大鼠粘蛋白基因的一部分。
