Chaussivert N, Conesa C, Shaaban S, Sentenac A
Service de Biochimie et Génétique Moléculaire, CEA-Saclay, Gif sur Yvette, France.
J Biol Chem. 1995 Jun 23;270(25):15353-8. doi: 10.1074/jbc.270.25.15353.
Transcription of yeast class III genes requires the sequential assembly of the general transcription factors TFIIIC and TFIIIB, and of RNA polymerase III, into an initiation complex composed of at least 25 polypeptides. The 70-kDa subunit of TFIIIB (TFIIIB70) is central in this network of interactions as it contacts both TATA-binding protein and a subunit of polymerase III. We show here that the TATA-binding protein interacts with the carboxyl-terminal part of TFIIIB70. TFIIIB70 also contacts TFIIIC (factor tau) via its tau 131 subunit. The protein domains of tau 131 and TFIIIB70 involved in this interaction, either positively or negatively, were mapped using the two-hybrid system. We provide evidence that intramolecular interactions mask functional domains in both polypeptides.
酵母III类基因的转录需要通用转录因子TFIIIC和TFIIIB以及RNA聚合酶III顺序组装成一个由至少25种多肽组成的起始复合物。TFIIIB的70 kDa亚基（TFIIIB70）在这个相互作用网络中处于核心地位，因为它既与TATA结合蛋白又与聚合酶III的一个亚基相互作用。我们在此表明，TATA结合蛋白与TFIIIB70的羧基末端部分相互作用。TFIIIB70还通过其tau 131亚基与TFIIIC（tau因子）相互作用。使用双杂交系统对tau 131和TFIIIB70中参与这种相互作用的蛋白质结构域进行了正向或负向定位。我们提供的证据表明，分子内相互作用掩盖了这两种多肽中的功能结构域。
