Cloning And Sequence Analysis On Mosquito Defensin Genes The Preliminary Development Of Novel Type Insectcide "KR-100

Background: Infectious diseases, such as malaria, filariasis, and dengue fever, etc, which is transmitted by mosquitoes, severely do harm to the human health. To control mosquitoes and insects is an effective way of controlling such diseases. Recent development of modern molecular biology and trans-gene techniques give us a new thought to prevent such diseases. The code gene of anti-pathogen is transmitted to mosquitoes, and is expressed by the drive of tissue or specific trigger. The expressed anti-pathogen then can change the growth and development of pathogens in bodies of mosquitoes, and intervene the transmission of pathogens by media of mosquitoes. The pathogens, which are transmitted by media of mosquitoes have to be able to avoid or defeat the defensive barriers in bodies of mosquitoes, such as peritrophic matyix, digestive enzyme, immune system, etc. The conversions of pathogens in different stages, such as invasion, maturity, etc are important to the disease spread. It is very important for the prevention strategies to illustrate the interactions between pathogens and media of mosquitoes, especially how pathogens try to avoid the defensive system in media of mosquitoes. To the infections of exterior pathogen, mosquitoes can form effective defensive system through activating inside cells and body fluid immune. At present, great concern is emphasized on a type of polypeptide, called "defender". The defender genes of mosquitoes firstly clone from aedes. Eggleston(2000) reports DNA structure of the defender genes of anopheles and its immune regulation. The study on the defender of mosquitoes has no report till now.This study clones the defender genes of common mosquitoes in our country. And the series of the genes are compared and analyzed. Objective: To clone the defensin genes from the main mosquito vectors in China.Methods: The genomic DNA and total RNA were extracted from Aedes aegypti, Aedes albopictus, Culex fatigans and Anopheles sinensis. Two pairs of primer were designed and synthesized based on the reported defensin gene. The PCR and RT-PCR were carried out and the PCR products were purified and sequenced.Results: The products with predicted size were amplified from A.aegypti, A.albopictus and A.sinensis. The sequence analysis showed that the amplified fragment from A.aegypti and A.albopictus had a high homology compared with the published defensin sequence but the homology between amplified fragments from A.sinensis and reported defensin sequence was very low. Conclusions: The defensin gene of A.aegypti and A.albopictus have been cloned. The homology of defensin genes among different mosquitoes is parallel to their genetic distances.