TAFII70 protein in Cajal bodies of the amphibian germinal vesicle

The localization of the TATA-binding protein (TBP) associated factor II70 ( TAFII70) in the germinal vesicle (GV) of newt oocytes was investigated. In spreads of GV content, anti-hTAFII70 monoclonal antibody (mAb) stained Caja l bodies (CBs) that were either attached to specific sites on the lampbrush chromosomes or free in the nucleoplasm. To confirm this localization the P wTAFII70 cDNA was cloned and myc-tagged transcripts injected into the oocyt e cytoplasm. Newly translated PwTAFII70 protein was detected a few hours la ter in the Cajal bodies. These data support the hypothesis that Cajal bodie s are the assembly sites of the transcription machinery of the oocyte nucle us. TAFII70 protein can play a role in lampbrush transcription; alternative ly TAFII70 can be considered a component in the subset of TFIID complexes t hat do not function during oogenesis, but are accumulated in the oocyte for later use during early development.