Artificial acceleration of HIV-1 reverse transcriptase turnover via the proteasome pathway

作者：Starodubova E S^*; Isaguliants M G; Karpov V L

来源：Molecular Biology, 2006, 40(6): 885-890.

DOI：10.1134/S0026893306060069

• HIV-1 reverse transcriptase
• ornithine decarboxylase
• DNA vaccine
• proteasomal degradation
• proteasome inhibitors

Since the proteasome plays a key role in antigen presentation in complex with MHC class I molecules, it is promising to increase the proteasomal targeting of proteins encoded by DNA vaccines. HIV-1 reverse transcriptase (RT), whose gene is included in DNA vaccines, was shown to degrade at a low rate: its half-life was estimated at 18-20 h. The proteasome inhibitors MG132 and epoxomycin increased the RT level in cells, suggesting proteasomal degradation of RT. The RT level in the presence of MG132 was twice as high as in the presence of proteasome-specific epoxomycin, which implicated other proteases in RT degradation as well. Proteasomal targeting can be increased by adding a strong degradation signal. Such signals are contained in mouse ornithine decarboxylase (ODC), which is unique in being rapidly degraded by the proteasome via a ubiquitin-independent mechanism. An RT-ODC fusion was constructed. Its half-life was 3 It, sixfold shorter than that of the wild-type RT. RT-ODC degradation was suppressed by the proteasome inhibitors ten times more efficiently as compared with RT degradation; i.e., the role of the proteasomal pathway grew higher. Thus, fusion with ODC increased the proteasomal degradation rate of RT, which could improve the immunogenicity of the corresponding DNA vaccine.

• 出版日期2006-12