de Carvalho D P, Coelho P S, de Almeida J C
Departamento de Morfologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, 14049-900, SP, Ribeirão Preto, Brazil.
Insect Biochem Mol Biol. 2000 Jul;30(7):541-8. doi: 10.1016/s0965-1748(00)00022-9.
During the last 30 h of the larval stage, the salivary glands of Bradysia hygida show the amplification of some genes, resulting in the formation of two successive groups of DNA puffs, which direct the synthesis of two different sets of polypeptides. Incubation of anterior (S1) salivary gland regions, at age E7, beginning of first group of DNA puffs activity, in culture medium for 2 to 10 h results in a decrease in the synthesis of the polypeptides characteristic of this period. However, during subsequent incubation (from E7 to E7+12 h-24 h), when the second group of DNA puffs is active, S1 regions were able to synthesize some polypeptides characteristic of this period. The role of 20-OH ecdysone was studied, in vitro and in vivo, during these two periods of protein synthesis in S1 regions. The presence of the hormone was shown to be necessary to maintain, in vitro, the synthesis of the first set of polypeptides and was strongly inhibitory, in vitro and in vivo, to the synthesis of the second set of polypeptides. Thus, it is likely that the activity of the two distinct groups of DNA puffs is under opposite 20-OH-ecdysone control mechanisms.
在幼虫期的最后30小时内，嗜菌瘿蚊的唾液腺会出现一些基因的扩增，导致形成两组连续的DNA胀泡，它们指导合成两组不同的多肽。在第一组DNA胀泡活动开始的E7期，将前（S1）唾液腺区域在培养基中培养2至10小时，会导致该时期特征性多肽的合成减少。然而，在随后的培养过程中（从E7到E7 + 12小时 - 24小时），当第二组DNA胀泡活跃时，S1区域能够合成该时期的一些特征性多肽。在S1区域这两个蛋白质合成时期，对20 - 羟基蜕皮激素的作用进行了体外和体内研究。结果表明，激素的存在对于在体外维持第一组多肽的合成是必要的，并且在体外和体内对第二组多肽的合成具有强烈的抑制作用。因此，两组不同的DNA胀泡的活性可能受相反的20 - 羟基蜕皮激素控制机制的调节。
