The Bioinformatics Analysis And Function Study Of Cathepsin Proteinases Gene From Silkworm, Bombyx Mori

There are many kinds of proteinases as key proteolytic proteinases in the development of insects. Such as yolk degrading proteinases in eggs during early embryonic development. So they play a variety of physiological roles including a role in food digestion. Several species of insects have been studied on proteinase since 1960's. such as Bombyx, Drosophila, Locusta. Maize weevil and Mosquito et al. Cysteine proteinase, serine proteinase and aspartic proteinase have been identified and purified from insects. Bombyx mori (silkworm) is the economic insect and model organism, the genome sequencing of it has been finished and bring us an unthinkable amount of information in 2003 .there are a few kinds of proteinases were reported.but there is some questions such as ,the variety of silkworm proteinase, the distribution and the localization in tissues of cathepsin proteinase in silkworm, and the physiological roles they play in silkworm.which actuate us to study it.Based on the silkworm genome database and EST database,we applied the biology informatic method,study the variety of proteinases , the distribution and the localization in tissues of cathepsin proteinase in silkworm, and cloned the new cathepsin D gene.then study the role of cahtepsin B in silkworm by RNAi. In this thesis, the work we did are showing:1. Based on the genome database and EST database ,we predict there are many kinds of proteinases in silkworm (the N0. are Bmb028908, Bmb029117,Bmb011691,Bmb024796, Bmb011691, Bmb024796,Bmb028908, Bmb013888, Bmb008297, Bmb029952, Bmb015815, Bmb020327, Bmb032550),mainly are cathepsin B,cathepsin D,cathepsin L,cathepsin O,cathepsin S, cathepsin F, cathepsin K.the cathepsin L (Bmb021457) and the cathepsin B (Bmb011691) were reported.2. To detect the distribution of cathepsin proteinase in development stages, which include Unfertilized egg, 24h embryo,3rd instar larva,5th instar day-3 larva,5th instar day-7 larva , mounting ,pupa. which were dectected at all stages include: cathepsin B Bmb028908, Bmb0 11691, Bmb024796, cathepsin L Bmb021457, Bmb023791 and cathepsin D Bmb008297, and there are two mRNA (1.0kb, 1. lkb) existed in Unfertilized egg,48h embryo,and w-1 embryo, predicted there is alternative splice in cathepsin D; expression specificity : cathepsin L (Bmb032720) existed at all stages except embryo;cathepsin S (Bmb013888) only existed mounting and pupa;3. To make clear the localization of cathepsin proteinase in Bombyx mori tissue will help us to understand its physiological function. We have studied the localization of cathepsin proteinase in tissues in B.mori at the 5th-instar day-3 larva by means of RT-PCR.the tissue include testis,...