Guénette S, Prichard R K, Matlashewski G
Institute of Parasitology, McGill University, Ste-Anne de Bellevue, Quebec, Canada.
Mol Biochem Parasitol. 1992 Feb;50(2):275-84. doi: 10.1016/0166-6851(92)90225-9.
We have examined the expression of beta-tubulin genes in the parasitic nematode, Brugia pahangi. A genomic library was constructed and screened by hybridization with a Haemonchus contortus beta-tubulin cDNA fragment which recognizes several B. pahangi beta-tubulin sequences, including sequences which correspond to the previously characterized beta 1-tubulin gene. The B. pahangi beta 2-tubulin gene was isolated by selecting clones which hybridize to the H. contortus beta-tubulin gene but which do not hybridize to the beta 1-tubulin gene. A partial sequence of the beta 2-tubulin gene confirms that it codes for a distinct beta-tubulin. Southern hybridization analyses show that the beta 2-tubulin sequence exists as a single copy gene within the B. pahangi genome. Expression of the beta 2-tubulin gene is developmentally regulated and the message is found predominantly in adult male worms, whereas the beta 1-tubulin gene is expressed in microfilariae and approximately equal levels of the transcript are found in male and female adult worms. During mRNA maturation the beta 1-tubulin mRNA of microfilariae and adult worms acquires a trans-spliced leader identical to the SL1 of Caenorhabditis elegans.
我们研究了寄生线虫彭亨布鲁线虫（Brugia pahangi）中β-微管蛋白基因的表达。构建了一个基因组文库，并用捻转血矛线虫（Haemonchus contortus）的β-微管蛋白cDNA片段进行杂交筛选，该片段可识别多个彭亨布鲁线虫β-微管蛋白序列，包括与先前鉴定的β1-微管蛋白基因相对应的序列。通过选择与捻转血矛线虫β-微管蛋白基因杂交但不与β1-微管蛋白基因杂交的克隆，分离出了彭亨布鲁线虫的β2-微管蛋白基因。β2-微管蛋白基因的部分序列证实它编码一种独特的β-微管蛋白。Southern杂交分析表明，β2-微管蛋白序列在彭亨布鲁线虫基因组中以单拷贝基因形式存在。β2-微管蛋白基因的表达受发育调控，其信使RNA主要在成年雄虫中发现，而β1-微管蛋白基因在微丝蚴中表达，在成年雄虫和雌虫中发现的转录本水平大致相等。在mRNA成熟过程中，微丝蚴和成年虫的β1-微管蛋白mRNA获得了一个与秀丽隐杆线虫（Caenorhabditis elegans）的SL1相同的反式剪接前导序列。
