Genomic localization of the human genes TAF1A, TAF1B and TAF1C, encoding TAF(I)48, TAF(I)63 and TAF(I)110 subunits of class I general transcription initiation factor SL1

Human SL1 is a general transcription initiation factor (GTF) essential for RNA polymerase I to start rRNA synthesis at class I promoters. It is compri sed of the TATA box-binding protein (TBP) and three TBP-associated factors (TAF(I)48, TAF(I)63 and TAF(I)110). We have determined that the human genes TAF1A, TAF1B and TAF1C, encoding these three TAF(I) polypeptides, are loca lized at 1q42, 2p25 and 16q24, respectively. All three genes are present as single copies in the human genome and map to different chromosomes, as sho wn by somatic cell hybrid panel and radiation hybrid panel analysis and FIS H. Two of these genes, TAF1C and TAF1B, are transcribed into multiple RNAs, as determined through Northern analysis of mRNA from various human organs and cell lines. If translated into different polypeptides, this could resul t in production of variant isoforms of SL1 with different activation potent ials. Copyright(C)2000S.KargerAG.Basel.