Paired box-containing (PAX) genes code for a family of transcription factors which have been implicated in the regulation of morphogenesis and pattern formation. The B cell-specific transcription factor PAX-5 (BSAP) is a member of this family whose in vivo function has recently been investigated. It is, however, still unkown how PAX-5 activates transcription of its target genes.
The project will focus on possible interactions between PAX-5 and the basal transcription machinery, especially with TFIID (TBP), TFIIB and TFIIH. Mutations will be generated into PAX-5 that specifically block these interactions. The mutants will be assayed in a PAX-5-dependent in vitro transcription system and in PAX-5-deficient pro-B cells for their biological relevance. Further studies will include the isolation of other PAX-5- interacting proteins using a yeast two hybrid screen or a biochemical approach based on affinity-chromatography of nuclear extracts.