Figure 1From: Dominant negative mutant Cyclin T1 proteins inhibit HIV transcription by specifically degrading TatConstruction of mutant CycT1 proteins. A. Structure of the cyclin box repeat domain (1–281) of CycT1. Two repeats of five α-helices each form the conserved cyclin box (blue). Flanking N- and C-terminal helices, which are important for the specificity of cyclins, are depicted in yellow and red, respectively. B. Schematic representation of C-terminally truncated wt CycT1 and the dominant negative CycT1-U7 mutant used in this study. Secondary structure of conserved α-helices (dotted regions in cyclin box 1 and hatched regions in cyclin box 2) together with two helices at N- and C-terminal (gray) locate in the N-terminal cyclin boxes in CycT1. Random mutations were introduced into the nine most conserved regions (shown by thin lines) in the cyclin box domain of a C-terminal truncation mutant of CycT1 (CycT1(1–280)). "-" in the CycT1-U7 sequence represents a deletion site. The truncated wt and mutant CycT1 employed in this study are also shown. C. A schematic representation of the full-length Cyclin T1. Amino acid motifs such as cyclin boxes, Tat-TAR recognition motif (TRM), coiled-coiled region, and PEST sequence are depicted.Back to article page