Molecular structure of the prothoracicotropic hormone gene in the northern house mosquito, Culex pipiens, and its expression analysis in association with diapause and blood feeding.
Molecular structure of the prothoracicotropic hormone gene in the northern house mosquito, Culex pipiens, and its expression analysis in association with diapause and blood feeding.
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DOI：
10.1111/j.1365-2583.2010.01058.x
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发表时间：
2011-04
影响因子：
2.6
通讯作者：
Denlinger DL
中科院分区：
文献类型：
--
作者：
Zhang Q;Denlinger DL
我们克隆的基因编码prothoracotropic激素（PTTH）在北方的家蚊，尖音库蚊，调查其在短日（滞育注定）和长日（nondiapause-destined）个人从四龄幼虫阶段到两个月的成年期，以及血餐后的表达谱。推导的Cupip-PTTH氨基酸序列含有7个具有特定间隔模式的半胱氨酸。序列比对表明，Cupip-PTTH与果蝇PTTH的同源性为23%，但与其他蚊子的PTTH的同源性≥ 59%。Cupip-PTTH具有与家蚕PTTH和一些脊椎动物神经生长因子相似的结构特征，具有半胱氨酸结基序。PTTH成绩单表现出每日循环配置文件在最后（第四）幼虫龄期，与高峰丰度发生在暗相后期。短日型幼虫的四龄比长日型幼虫长一天，导致幼虫和成虫较大。这一额外的幼虫发育日与一个额外的PTTH周期有关。没有观察到周期在蛹，但PTTH成绩单略高于短日蛹比长日蛹在整个蛹阶段。PTTH的表达持续在一个几乎恒定的水平滞育的成年女性的第一个月，但随后下降约50%，而表达下降，在成年期的开始，在nondiapausing女性，然后保持在一个低水平，只要女性被剥夺了血餐。但是，当给非滞育雌性动物提供血餐时，PTTH转录物在2小时内升高约7倍，并保持升高24小时。少数滞育雌性（约10%）在靠近宿主时会吸食血液，但大部分血液会被排出，这样的食物不会产生成熟的卵子。然而，升高PTTH mRNA的表达也观察到滞育的女性被强制喂食。因此，我们的研究结果指出，短日照和长日照蚊子之间PTTH表达的几个区别，但这两种类型的女性通过升高PTTH mRNA水平对血餐作出反应。
We cloned the gene that encodes prothoracicotropic hormone (PTTH) in the northern house mosquito, Culex pipiens, investigated its expression profile in short-day (diapause-destined) and long-day (nondiapause-destined) individuals from the fourth instar larval stage through two-months of adulthood, as well as after a blood meal. The deduced Cupip-PTTH amino acid sequence contains seven cysteines with a specific spacing pattern. Sequence alignment suggests that Cupip-PTTH is 23% identical to Drosophila melanogaster PTTH, but is ≥ 59% identical to the PTTHs of other mosquitoes. Cupip-PTTH has structural characteristics similar to Bombyx mori PTTH and some vertebrate nerve growth factors with cysteine-knot motifs. PTTH transcripts exhibit a daily cycling profile during the final (fourth) larval instar, with peak abundance occuring late in the scotophase. The fourth larval instar is one day longer in short-day larvae than in long-day larvae, resulting in larger larvae and adults. This additional day of larval development is associated with one extra PTTH cycle. No cycling was observed in pupae, but PTTH transcripts were slightly higher in short-day pupae than in long-day pupae throughout much of the pupal stage. PTTH expression persisted at a nearly constant level in diapausing adult females for the first month but then dropped approximately 50%, while expression decreased at the beginning of adulthood in nondiapausing females and then remained at a low level as long as the females were denied a blood meal. But, when nondiapausing females were offered a blood meal, PTTH transcripts rose approximately 7-fold in 2 h and remained elevated for 24 h. A few diapausing females (~ 10%) will take a blood meal when placed in close proximity of a host, but much of the blood is ejected and such meals do not result in mature eggs. Yet, elevated PTTH mRNA expression was also observed in diapausing females that were force fed. Our results thus point to several distinctions in PTTH expression between short-day and long-day mosquitoes, but both types of females responded to a blood meal by elevating levels of PTTH mRNA.