HORMONAL-REGULATION OF EPIDERMAL METAMORPHOSIS INVITRO - CONTROL OF EXPRESSION OF A LARVAL-SPECIFIC CUTICLE GENE
HORMONAL-REGULATION OF EPIDERMAL METAMORPHOSIS INVITRO - CONTROL OF EXPRESSION OF A LARVAL-SPECIFIC CUTICLE GENE
复制标题
DOI：
10.1016/0012-1606(91)90429-7
复制
发表时间：
1991-04-01
影响因子：
2.7
通讯作者：
RIDDIFORD, LM
中科院分区：
文献类型：
--
作者：
HIRUMA, K;HARDIE, J;RIDDIFORD, LM
以烟草天蛾四龄幼虫的表皮为材料，建立了烟草天蛾变态的体外培养体系，从细胞和分子水平研究了激素对变态的调控作用。立即暴露于4 × 10−6，M20-羟基蜕皮激素（20-HE）超过8小时，然后在无水培养基中暴露24小时，导致新的幼虫角质层形成。相比之下，孵化在无菌培养基中超过24小时，然后暴露于20-HE允许蛹角质层合成。幼虫特异性表皮基因LCP-14的表达在体外蜕皮期间对20-HE的反应中迅速停止（半衰期：约20天）。6小时），即使在3 × 10 - 8，MJH I.放线菌酮阻止了20-HE的这种抑制作用，表明20-HE不直接作用于该基因。与α-鹅膏蕈碱孵育表明LCP-14的半衰期超过10小时。因此，20-HE必须抑制基因转录并使mRNA不稳定。LCP-14 mRNA随后再次出现24小时后，暴露于无酶培养基，表明抑制是暂时的。相比之下，当JH和它的影响是不存在的预孵育后，在无菌培养基48小时，20-HE造成永久抑制LCP-14 mRNA，因为mRNA没有重新出现后，删除20-HE。将第2天的5龄幼虫表皮暴露于3 × 10−7，M20-HE，在没有JH I的情况下导致蛹定型，也永久抑制LCP-14基因表达。
Fourth (penultimate) instar larval epidermis of the tobacco hornworm,Manduca sexta, was used to develop anin vitroculture system to study the hormonal control of metamorphosis at both the cellular and the molecular level. Immediate exposure to 4 × 10−6,M20-hydroxyecdysone (20-HE) for more than 8 hr, followed by hormone-free medium for 24 hr, caused the formation of a new larval cuticle. By contrast, incubation in hormone-free medium for more than 24 hr prior to exposure to 20-HE allowed pupal cuticle synthesis. The cessation of expression of the larval-specific cuticular gene LCP-14 occurred rapidly in response to 20-HE during the larval moltin vitro(half-life: ca. 6 hr), even in the presence of 3 × 10−8,MJH I. This suppression by 20-HE was prevented by cycloheximide, indicating that 20-HE does not act directly on this gene. Incubation with α-amanitin showed that the half-life of LCP-14 was more than 10 hr. Thus, 20-HE must both suppress gene transcription and destabilize the mRNA. LCP-14 mRNA subsequently reappeared 24 hr after exposure to hormone-free medium, indicating that suppression was temporary. By contrast, when JH and its effects were absent after preincubation in hormone-free medium for 48 hr, 20-HE caused permanent suppression of LCP-14 mRNA, since the mRNA did not reappear after removal of 20-HE. Exposure of Day 2 fifth instar larval epidermis to 3 × 10−7,M20-HE, which causes pupal commitment in the absence of JH I, also permanently suppressed LCP-14 gene expression.