The TFIID Components Human TAF_II140 andDrosophila BIP2 (TAF_II155) Are Novel Metazoan Homologues of Yeast TAF_II47 Containing a Histone Fold and a PHD Finger

Abstract

The RNA polymerase II transcription factor TFIID comprises the TATA binding protein (TBP) and a set of TBP-associated factors (TAF_IIs). TFIID has been extensively characterized for yeast, Drosophila, and humans, demonstrating a high degree of conservation of both the amino acid sequences of the constituent TAF_IIs and overall molecular organization. In recent years, it has been assumed that all the metazoan TAF_IIs have been identified, yet no metazoan homologues of yeast TAF_II47 (yTAF_II47) and yTAF_II65 are known. Both of these yTAF_IIs contain a histone fold domain (HFD) which selectively heterodimerizes with that of yTAF_II25. We have cloned a novel mouse protein, TAF_II140, containing an HFD and a plant homeodomain (PHD) finger, which we demonstrated by immunoprecipitation to be a mammalian TFIID component. TAF_II140 shows extensive sequence similarity toDrosophila BIP2 (dBIP2) (dTAF_II155), which we also show to be a component of DrosophilaTFIID. These proteins are metazoan homologues of yTAF_II47 as their HFDs selectively heterodimerize with dTAF_II24 and human TAF_II30, metazoan homologues of yTAF_II25. We further show that yTAF_II65 shares two domains with the Drosophila Prodos protein, a recently described potential dTAF_II. These conserved domains are critical for yTAF_II65 function in vivo. Our results therefore identify metazoan homologues of yTAF_II47 and yTAF_II65.

ACKNOWLEDGMENTS

We thank S. Sanders and P. A. Weil for the yTAF_II65 null strain and cDNA, G. Mengus for the Drosophila nuclear extract, A. Ferrus and A. Hernandez for sharing their data prior to publication, Y. Nakatani for the anti-dTBP and -dTAF_II230 antisera, S. Hollenberg for the generous gift of yeast strain L40, V. Calco for excellent technical assistance, M. Oulad-Abdelghani and the monoclonal antibody facility, P. Eberling for peptide synthesis, S. Vicaire and D. Stephane for DNA sequencing, the staff of cell culture and oligonucleotide facilities, and B. Boulay for help with illustrations.

Y.-G.G. was supported by a fellowship from the Ligue National Contre le Cancer, S.T. was supported by a fellowship from the Région Alsace, and S.M. was supported by a short-term EMBO fellowship. This work was supported by grants from the CNRS, the INSERM, the Hôpital Universitaire de Strasbourg, the Ministère de la Recherche et de la Technologie, the Association pour la Recherche contre le Cancer, the Ligue Nationale contre le Cancer, and the Human Frontier Science Programme and by grant GREG#59/95 to J.-L.C.