| Modification Notes |
Maximal expression of G1 cyclins is induced by the heterodimeric transcription factor complex, which is composed of the DNA-binding subunit, Swi4 (also designated Art1), and Swi6 (1-3). In addition to binding Swi4, Swi6 forms a complex with Mbp1 that activates S-phase cyclins and genes involved in DNA synthesis (4). Rpb1 is the largest subunit of the yeast RNA polymerase II (5). Srb4 is a basal transcription factor that is essential for the establishment of the transcription initiation apparatus (5). Ssn6, a tandem tetratricopeptide repeat-containing protein, associates with Tup1 to form a general transcriptional repression complex (6). The yeast SNF-SWI complex is required for transcriptional activation of diverse genes and has been shown to alter chromatin structure (7). This complex has at least 10 components, including Snf2 (alternatively designated Swi2, Ric1, or Gam1), Snf5, Snf6, Swi1 (alternatively designated Adr6 or Gam3), and Swi3, and has been widely conserved (7). Transcriptional activators, Snf2 and Snf5, function by antagonizing repression mediated by nucleosomes (8). |