High levels of transcription are associated with elevated mutation rates in 
yeast, a phenomenon referred to as transcription-associated mutation (TAM). The 
transcription-associated increase in mutation rates was previously shown to be 
partially dependent on the Rev3p translesion bypass pathway, thus implicating 
DNA damage in TAM. In this study, we use reversion of a pGAL-driven lys2DeltaBgl 
allele to further examine the genetic requirements of TAM. We find that TAM is 
increased by disruption of the nucleotide excision repair or recombination 
pathways. In contrast, elimination of base excision repair components has only 
modest effects on TAM. In addition to the genetic studies, the lys2DeltaBgl 
reversion spectra of repair-proficient low and high transcription strains were 
obtained. In the low transcription spectrum, most of the frameshift events 
correspond to deletions of AT base pairs whereas in the high transcription 
strain, deletions of GC base pairs predominate. These results are discussed in 
terms of transcription and its role in DNA damage and repair.