Function Of Vitellogenin Gene In Chrysopa Septempunctata

Vitellogenin is a phospholipoglycoprotein peculiar existing in all oviparous organisms, The proteinprovided nutrition and functional materials for the embryo development, having important physiologicalfunctions. The research cloned the vitellogenin gene in Neuroptera insect chrysopa septempunctata,exploring the the physiological function of Neuroptera natural enemy insect C. septempunctata. At thesame time, the Housekeeping gene Actin was also cloned, the vitellogenesis process of C.septempunctata vitellogenin was proclaimed from transcription and expression level. The physiologicalfunction of vitellogenin gene in C. septempunctata was systematically studied by using RNAinterference.The main results were summarized as follows:1. Coding region of C. septempunctata vitellogenin gene was cloned from female adult afteremergence5-7days by using RACE and RT-PCR. The amino acid sequence of vitellogenin proteinshowed high homology to those of vitellogenin from other insects and had conserved domain ofvitellogenin gene. The protein was designated as CSVg.2. Actin gene of C. septempunctata was cloned by RT-PCR and RACE，providing reference genefor the transcriptional analysis of vitellogenin gene in C. septempunctata. Vitellogenin gene existed in C.septempunctata male and female adults by RT-PCR identification, Vitellogenin gene startedtranscription4days after emergence in C. septempunctata female adults, reaching its peak in10daysafter emergence, and then declined gradually. The vitellogenin gene was also detected in C.septempunctata male adults4days after emergence, but the differences were not significant in differentdevelopmental time. The expression of vitellogenin protein was detected by ELISA, discovering that thetrend of expression and transcription of vitellogenin was consistent.3. Four different fragment of vitellogenin was amplified by polymerase chain reaction,successfully builded the prokaryotic expression vector and transformed into the Escherichia coli HT115,and acquired CSVg dsRNA.4. We guided Four different fragment of CSVg dsRNA into C. septempunctata adult bymicroinjection, the GFP dsRNA was as the control. The research resuls indicated that the vitellogeninwas inordinately reduced after injecting CSVg dsRNA comparing to the control, indicating that thevitellogenin was successfully interfered. The physiological function research of natural enemy insect C.septempunctata indicated that the egg laid during the first five days and the hatching rate of egg waslower than the control after interfering the vitellogenin of female.