Subunit interactions in yeast transcription/repair factor TFIIH - Requirement for Tfb3 subunit in nucleotide excision repair

ih yeast strain harboring a temperature-sensitive allele of TFB3 (tfb3(ts)) , the 38-kDa subunit of the RNA polymerase II transcription/nucleotide exci sion repair factor TFIIH, was found to be sensitive to ultraviolet (UV) rad iation and defective for nucleotide excision repair in vitro, Interestingly , tfb3(ts) failed to grow on medium containing caffeine. A comprehensive pa irwise two-hybrid analysis between yeast TFIIH subunits identified novel in teractions between Rad3 and Tfb8, Tfb4 and Ssl1, as well as Ssl2 and Tfb2. These interactions have facilitated a more complete model of the structure of TFIIH and the nucleotide excision repairosome.