Promoter-selective properties of the TBP-Related factor TRF1

The TATA-binding protein (TBP)-related factor 1 (TRF1) is expressed in a ti ssue-restricted fashion during Drosophila embryogenesis and may serve as a promoter-specific recognition factor that can replace TBP in regulating tra nscription. However, bona fide target promoters that would preferentially r espond to TRF1 have remained elusive. Polytene chromosome staining, chromat in immunoprecipitation, direct messenger RNA analysis, and transient cotran sfection assays identified the Drosophila gene tudor as containing a TRF1-r esponsive promoter. Reconstituted in vitro transcription reactions and deox yribonuclease I footprinting assays confirmed the ability of TRF1 to bind p referentially and direct transcription of the tudor gene from an alternate promoter. Thug, metazoans appear to have evolved gene-selective and tissue- specific components of the core transcription machinery to regulate gene ex pression.