Interactions between Human Cyclin T, Tat, and the Transactivation Response Element (TAR) are Disrupted by a Cysteine to Tyrosine Substitution Found in Mouse Cyclin T
Abstract
The transcriptional transactivator Tat from HIV binds to the transactivation response element (TAR) RNA to increase rates of elongation of viral transcription. Human cyclin T supports these interactions between Tat and TAR. In this study, we report the sequence of mouse cyclin T and identify the residues from positions 1 to 281 in human cyclin T that bind to Tat and TAR. Mouse cyclin T binds to Tat weakly and is unable to facilitate interactions between Tat and TAR. Reciprocal exchanges of the cysteine and tyrosine at position 261 in human and mouse cyclin T proteins also render human cyclin T inactive and mouse cyclin T active. These findings reveal the molecular basis for the restriction of Tat transactivation in rodent cells.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- February 1999
- DOI:
- 10.1073/pnas.96.4.1285
- Bibcode:
- 1999PNAS...96.1285F