Platt A, Reece R J
School of Biological Sciences, The University of Manchester, 2.205 Stopford Building, Oxford Road, Manchester M13 9PT, UK.
EMBO J. 1998 Jul 15;17(14):4086-91. doi: 10.1093/emboj/17.14.4086.
Saccharomyces cerevisiae responds to galactose as the sole source of carbon by activating the GAL genes encoding the enzymes of the Leloir pathway. Here, we show in vitro that the switch from repressed to activated gene expression involves the interplay of three proteins [an activator (Gal4p), a repressor (Gal80p) and an inducer (Gal3p)] and two small molecules (galactose and ATP). We also show that the galactose- and ATP-dependent interaction between Gal3p and Gal80p occurs without disruption of the Gal80p-Gal4p interaction. Thus, Gal3p-mediated activation of transcription occurs via the formation of a tripartite protein complex.
酿酒酵母通过激活编码Leloir途径中酶的GAL基因来响应半乳糖作为唯一碳源的情况。在此,我们在体外表明,从基因表达被抑制到被激活的转变涉及三种蛋白质[一种激活剂(Gal4p)、一种阻遏物(Gal80p)和一种诱导物(Gal3p)]以及两种小分子(半乳糖和ATP)之间的相互作用。我们还表明,Gal3p与Gal80p之间依赖半乳糖和ATP的相互作用发生时,Gal80p - Gal4p的相互作用并未被破坏。因此,Gal3p介导的转录激活是通过形成三方蛋白质复合物而发生的。