Construction Of CDNA Library From Apis Cerana Venom Gland And Analysis Of Expressed Sequence Tag(EST)

Chinese honeybee (Apis cerana cerana)is a vital economic insect,it is largely bred in China.The honeybee's venom gland is a complex organ.The characterization of the molecular framework of the venom gland at the level of expressed genes will facilitate the understanding of the venom gland biology.The purposes of this study were to acquire an initial assessment of the qualitative and quantitative diversity of gene expression in the venom gland of Apis cerana and to determine the extent that genes with venom gland- restricted expression can be assessed using an expressed sequence tag approach.We have constructed a directional cDNA library from Apis cerana venom gland and partially sequenced the 5'end of 1152 randomly selected cDNA clones.The sequence of each EST was edited to remove vector and adapter sequences,and poor-quality sequences using phredphrap.Totally,1121 clones were acquired,representing 944 unique genes.To annotate these ESTs,Edited sequences were compared with protein databases (GenBank)at the National Center for Biotechnology Information (NCBI)using BLASTX programs.We found 215(22.77%)ESTs encodes proteins with function-annotation,while 286(30.30%)ESTs encodes function-unknown proteins,and the other 443(46.93%)ESTs had no matches in GenBank.To elucidate the molecular mechanism occurring in venom gland,we further classified the 215 function- annotated ESTs according to the cellular processes they involved.We found EST counts of melittin as well as its precursors accounts for 2.05% of the total ESTs sequenced in this project,indicating the expression abundance of melittin genes was very heavy.Another venom peptide,apamin,also was detected highly expressed in venom...