Program

Poster Presentations

Day 2, May 16（Wed.）　　Poster

2P-49（3A-O1-P-1030）　　PDF

Nascent protein analysis and its application for novel protein identification

(¹AIST, ²Univ. Tokyo)
^oShungo Adachi¹, Akihisa Kato², Yasushi Kawaguchi², Tohru Natsume¹

Do we already know all proteins? The answer is no. We usually predict protein sequences from the corresponding mRNA sequences; however, there are untranslated regions and alternative reading frames within mRNAs, and thus it remains difficult to identify all protein sequences. Here we illustrate an approach to identify novel viral and human proteins. We initially focused on herpes simplex type 1 virus (HSV1) and constructed a new protein database that contains all known human protein sequences and six giant protein sequences in which six kinds of reading frames of the whole 150 kb HSV1 genome sequence were converted into amino acid sequences. We constructed a new database because it is not possible to identify proteins that are not listed in the protein database. We then prepared HSV1 infected and uninfected human cells followed by labeling and purification of nascent proteins to analyze exclusively viral proteins. We performed MS analysis to identify novel HSV1 proteins. Using this approach, we succeeded in identifying 13 novel HSV1 protein candidates and found that at least one was produced in HSV1 infected cells and involved in the pathogenicity. We also applied this strategy to human mRNAs and again succeeded in finding novel protein candidates produced from alternative reading frames of many mRNAs. These results suggest that there are still many novel proteins to be identified and believe that our strategy is very useful in shedding light on these unidentified proteins.