Wang X Y, Cole K D, Law J H
Department of Biochemistry, University of Arizona, Tucson 85721.
Gene. 1989 Aug 15;80(2):259-68. doi: 10.1016/0378-1119(89)90290-4.
A microvitellogenin (mVg)-coding gene (mvg) has been isolated from a lambda phage library prepared from the tobacco hornworm, Manduca sexta. One of the lambda clones had a 15-kb insert and contained the entire mvg gene. A DNA fragment (3.0 kb) containing this mvg gene has been sequenced. Southern blot analysis showed that there may be more than one mvg gene in M. sexta. The putative transcriptional start point (tsp) for the cloned mvg was determined by primer extension analysis. This gene contains a single intron in the 5'-noncoding region. The 5'-flanking sequence was compared to the 5'-conserved regions of yolk polypeptide-encoding genes (yp) of Drosophila melanogaster. Two regions were found in the 5'-flanking sequence of the mvg gene that have 66% similarity to the D. melanogaster yp consensus sequence that is believed to be involved in gene expression controlled by ecdysteroids. Furthermore, the sequences flanking these two regions are also similar to the ecdysone-responsive elements found in several genes of D. melanogaster. In fact, preliminary experiments showed that mVg mRNA synthesis is induced by the 20-hydroxyecdysone. Four regions of the mvg gene resemble the upstream conserved regions of the two vitellogenin-encoding genes of the locust, Locusta migratoria. The nucleotide sequence of mvg has 70% similarity to the sequence of one or more of the 30-kDa hemolymph proteins of Bombyx mori. This indicates a very close evolutionary relationship between these proteins.
已从烟草天蛾（Manduca sexta）制备的λ噬菌体文库中分离出一个微卵黄原蛋白（mVg）编码基因（mvg）。其中一个λ克隆有一个15 kb的插入片段，包含整个mvg基因。已对包含该mvg基因的一个DNA片段（3.0 kb）进行了测序。Southern印迹分析表明，烟草天蛾中可能存在不止一个mvg基因。通过引物延伸分析确定了克隆的mvg的推定转录起始点（tsp）。该基因在5'-非编码区含有一个内含子。将5'-侧翼序列与黑腹果蝇卵黄多肽编码基因（yp）的5'-保守区进行了比较。在mvg基因的5'-侧翼序列中发现了两个区域，它们与黑腹果蝇yp共有序列有66%的相似性，据信该共有序列参与由蜕皮类固醇控制的基因表达。此外，这两个区域侧翼的序列也与在黑腹果蝇几个基因中发现的蜕皮激素反应元件相似。事实上，初步实验表明，mVg mRNA的合成受20-羟基蜕皮酮诱导。mvg基因的四个区域类似于飞蝗（Locusta migratoria）两个卵黄原蛋白编码基因的上游保守区。mvg的核苷酸序列与家蚕30 kDa血淋巴蛋白中一个或多个蛋白的序列有70%的相似性。这表明这些蛋白之间存在非常密切的进化关系。
