21118326
not annotated - annotated - LINNAEUS only
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.
We cloned the gene that encodes prothoracicotropic hormone (PTTH) in the northern house mosquito, Culex pipiens, and investigated its expression profile in short-day (diapause-destined) and long-day (nondiapause-destined) individuals from the fourth-instar larval stage to 2 months of adulthood, as well as after a blood meal. The deduced C. pipiens PTTH (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 those of 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 occurring late in the scotophase. The fourth-larval instar stage 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 by -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. However, 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 to 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.
Ann file
T1 Species 66 89 northern house mosquito
N1 Reference T1 Taxonomy:7175
T2 Species 91 104 Culex pipiens
N2 Reference T2 Taxonomy:7175
T3 Species 257 280 northern house mosquito
N3 Reference T3 Taxonomy:7175
T4 Species 282 295 Culex pipiens
N4 Reference T4 Taxonomy:7175
T5 Species 523 533 C. pipiens
N5 Reference T5 Taxonomy:7175
T6 Species 694 717 Drosophila melanogaster
N6 Reference T6 Taxonomy:7227
T7 Species 843 854 Bombyx mori
N7 Reference T7 Taxonomy:7091