Guild G M, Shore E M
J Mol Biol. 1984 Nov 5;179(3):289-314. doi: 10.1016/0022-2836(84)90067-6.
The 90BC locus on the polytene chromosomal map of Drosophila melanogaster contains the structural gene for a third-instar, salivary gland-specific, polyadenylated RNA (the group V RNA). This also belongs to the intermolt puff set whose dispersed and co-ordinately regulated members are (1) transcriptionally active in the salivary gland during the third-instar developmental stage and (2) comprise (at least in part) the structural genes for a set of salivary gland secretion proteins. Previous developmental studies of the group V intermolt gene (located cytogenetically within the 90B3-8 interval) suggest that it controls the expression of a salivary gland secretion protein. By analyzing different D. melanogaster laboratory stocks for variation in group V gene expression, we have been able to correlate the presence of the group V RNA with the salivary gland secretion protein P4. In vitro translation experiments show that the salivary gland messenger RNA population derived from a stock that fails to synthesize the group V RNA does not direct the synthesis of a polypeptide similar in molecular weight to protein P4. In addition, cloned genomic DNA segments complementary to the group V RNA are capable of arresting the in vitro translation of this protein. Comparative two-dimensional fractionation of cysteine-labeled, protease-generated peptides shows that (1) the in vitro translation product arrested by group V gene DNA is biochemically very similar to or identical with the salivary gland secretion protein P4, and (2) protein P4 is equivalent to the salivary gland secretion protein previously designated SGS-5. Since designations of the latter type have been employed in naming the genetic loci that represent the structural genes for the salivary gland secretion protein gene set, the group V gene (previous designation) represents the SGS-5 structural gene and its appropriate genetic designation should now be Sgs-5.
在黑腹果蝇多线染色体图谱上的90BC位点包含一个第三龄幼虫唾液腺特异性多聚腺苷酸化RNA（V组RNA）的结构基因。它也属于蜕皮间期胀泡组，该组中分散且协同调控的成员有：（1）在第三龄幼虫发育阶段在唾液腺中转录活跃；（2）（至少部分地）构成一组唾液腺分泌蛋白的结构基因。先前对V组蜕皮间期基因（细胞遗传学定位在90B3 - 8区间内）的发育研究表明，它控制一种唾液腺分泌蛋白的表达。通过分析不同的黑腹果蝇实验室品系中V组基因表达的差异，我们已能够将V组RNA的存在与唾液腺分泌蛋白P4联系起来。体外翻译实验表明，源自一个无法合成V组RNA的品系的唾液腺信使RNA群体不能指导合成一种分子量与蛋白P4相似的多肽。此外，与V组RNA互补的克隆基因组DNA片段能够阻止该蛋白的体外翻译。对用半胱氨酸标记、蛋白酶产生的肽进行的二维比较分级分离表明：（1）被V组基因DNA阻止的体外翻译产物在生化性质上与唾液腺分泌蛋白P4非常相似或相同；（2）蛋白P4等同于先前命名为SGS - 5的唾液腺分泌蛋白。由于后一种类型的命名已被用于命名代表唾液腺分泌蛋白基因集结构基因的遗传位点，V组基因（先前的命名）代表SGS - 5结构基因，其合适的基因命名现在应为Sgs - 5。
