Developmental expression of three genes for larval cuticular proteins of the tobacco hornworm, Manduca sexta.
Developmental expression of three genes for larval cuticular proteins of the tobacco hornworm, Manduca sexta.
复制标题
烟草天蛾幼虫角质层蛋白三个基因的发育表达。
DOI：
10.1016/0012-1606(86)90075-8
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发表时间：
1986
影响因子：
2.7
通讯作者：
Rebers,J
中科院分区：
文献类型：
--
作者：
Riddiford,LM;Baeckmann,A;Hice,RH;Rebers,J
分离得到了烟草角虫（Manduca sexta）幼虫表皮蛋白的3个cDNA克隆，分别编码12.8、13.3和14.6 kDa。对不同时期腹部表皮RNA的杂交表明，12.8和13.3 kDa蛋白的基因仅在幼虫时期表达。相比之下，14.6 kDa蛋白的基因在摄食期和幼虫生长期的整个节段中表达，然后仅在舌蛹和成虫的囊内沉积期间的柔性节段间表达。定量RNA斑点杂交表明，在蜕皮激素滴度较高时，各蛋白的RNA在幼虫蜕皮过程中消失，在蜕皮前囊内沉积过程中重新出现。所有这些都在流浪开始时表皮变成蛹时消失。在室外条件下，将4龄幼虫表皮暴露于20-羟基蜕皮素（20HE）中，导致新幼虫角质层形成48小时，而这些rna在18小时内消失。将第2天的5龄表皮暴露于体外20HEin会导致这些rna的抑制，在编码12.8和13.3 kDa蛋白的rna的情况下，这种抑制可以通过同时暴露于甲基戊二烯（一种幼年激素（JH）模拟物）来部分阻止。相比之下，14.6 kDa蛋白的RNA被单独暴露于甲基戊二烯抑制。因此，这些幼虫角质层基因中的每一个都被高表皮激素关闭；JH的存在与否决定了这种抑制是否在某些或所有细胞中是永久性的。
Three cDNA clones coding for the 12.8, 13.3, and 14.6 kDa larval cuticular proteins of the tobacco hornworm,Manduca sexta, were isolated and characterized. Hybridization to abdominal epidermal RNA from different stages showed that the genes for the 12.8 and 13.3 kDa proteins were expressed only during larval life. By contrast, the gene for the 14.6 kDa protein was expressed throughout the segment during the feeding, growing larval stages, then only in the flexible intersegmental regions during the deposition of endocuticle in the pharate pupa and adult. Quantitative RNA dot blot hybridizations showed that the RNA for each protein disappeared during the larval molt when the ecdysteroid titer was high, then reappeared during the preecdysial deposition of endocuticle. All disappeared when the epidermis became pupally committed at the onset of wandering. Exposure of the fourth instar epidermis to 20-hydroxyecdysone (20HE)in vitrounder conditions that lead to the formation of a new larval cuticle by 48 hr caused the disappearance of these RNAs by 18 hr. Exposure of Day 2 fifth instar epidermis to 20HEin vitrocaused a depression of these RNAs which in the case of the RNAs coding for the 12.8 and 13.3 kDa proteins was partially prevented by simultaneous exposure to methoprene, a juvenile hormone (JH) mimic. By contrast, the RNA for the 14.6 kDa protein was suppressed by exposure to methoprene alone. Thus, each of these larval cuticular genes is turned off by high ecdysteroid; the presence or absence of JH determines whether or not this suppression is permanent in some or all cells.