Kalhok S E, Tabak L M, Prosser D E, Brook W, Downe A E, White B N
Department of Biology, Queen's University, Kingston, Ontario, Canada.
Insect Mol Biol. 1993;2(2):71-9. doi: 10.1111/j.1365-2583.1993.tb00127.x.
In order to understand the regulation of trypsin genes by the blood meal, we constructed a cDNA library from mRNA isolated from midguts of blood-fed female Aedes aegypti. The library was screened with a Drosophila melanogaster trypsin-like gene; twelve cDNAs were isolated and sequenced. Two clones were 846 bp and 788 bp long with 762 bp and 716 bp open reading frames, respectively. The cDNAs were identified as coding for serine proteases by the presence of conserved serine, histidine and aspartic acid residues; the presence of an aspartate residue at position 176 suggests that the clones were derived from trypsin-like gene transcripts rather than chymotrypsin or other serine proteases. One of the clones contained a 5' untranslated region and coding regions for putative signal and activation peptides, suggesting that the product is secreted as an inactive zymogen and processed by autoactivation. Southern analysis of genomic DNA suggests that trypsin is encoded by a multigene family in A. aegypti.
为了了解血餐对胰蛋白酶基因的调控，我们从吸食血液的雌性埃及伊蚊中肠分离的mRNA构建了一个cDNA文库。用果蝇类胰蛋白酶基因筛选该文库；分离并测序了12个cDNA。两个克隆分别长846 bp和788 bp，开放阅读框分别为762 bp和716 bp。通过保守的丝氨酸、组氨酸和天冬氨酸残基的存在，将这些cDNA鉴定为编码丝氨酸蛋白酶；在第176位存在天冬氨酸残基表明这些克隆来源于类胰蛋白酶基因转录本，而非胰凝乳蛋白酶或其他丝氨酸蛋白酶。其中一个克隆包含一个5'非翻译区以及假定的信号肽和激活肽编码区，这表明该产物作为无活性的酶原分泌，并通过自身激活进行加工。基因组DNA的Southern分析表明，胰蛋白酶由埃及伊蚊中的一个多基因家族编码。
