Application Of Bioinformatics In Bombyx Moriand The Study On The BmRGPC Protein From Silkworm Pupae

Bombyx mori is not only an important research model organism, but also the biological resources with Chinese characteristic, and its cocoon after the pupa is not only having important medicinal value and nutritional value, but also as an bioreactor to express various kinds of important pharmaceutical proteins. Comparing with the larva, the cocoon can be easily stored and do not require rearing, so the study of the silkworm pupa has important biological significance[1].In order to study the expression characteristics of proteins during the silkworm metamorphosis, particularly in the transitional period- the state of pupa, we use the bioinformatic methods, based on the existed cDNA library[2], to construct the protein database A, in which the total number of records is 4104.After the successful completion of the silkworm whole-genome sequencing, about 20000 silkworm genes were found[3]. By using the BGI GENE FINDER(BGF) server to scan from the existing silkworm genome sequences, the coverage of which was 6×, we got a protein database B, in which the total number of records is 14,632. At the same time the large-scale sequencing was performed by using the mass spectrometry technology, and a total of 81000 were obtained from valid MS peptide sequences. After bioinformatics analysis, a total of 55400 peptides, which scored above the threshold, were selected to construct the database C.Because all the three protein databases were derived from silkworm, we use the bioinformatic techniques to analysis the records. After comparing the database C with the other two databases, we found that 6649 and 250 proteins could be matched, and the ratio of each database approximately 45.4% and 7.8% respectively. After further analysis of the matched proteins, the result showed that there were 1393 proteins containing at least one transmembrane regions and 976 proteins containing a signal peptide from the matched proteins. We found that a protein was associated with the tumor suppressor named Ras-related GTP-binding Protein C (BmRGPC). This protein contained total length of 387 amino acids, and its corresponding full-length opening reading frame(ORF) was 1164bp. We found that it was highly conserved during evolution, and it was a key protein in the Ras signaling pathway. In other species, it mainly played the role of inhibitors of cancer. There was no research article about this protein in silkworm, so we carried out molecular cloning and prokaryotic expression studies to fill the gaps.