Characterizing the roles of Met31 and Met32 in coordinating Met4-activated transcription in the absence of Met30.
Characterizing the roles of Met31 and Met32 in coordinating Met4-activated transcription in the absence of Met30.
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DOI：
10.1091/mbc.e11-06-0532
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发表时间：
2012-05
影响因子：
3.3
通讯作者：
Lee TA
中科院分区：
文献类型：
--
作者：
Carrillo E;Ben-Ari G;Wildenhain J;Tyers M;Grammentz D;Lee TA
为了检查转录因子家族成员之间靶基因表达如何协调，使用转录和全基因组结合阵列检查了一个简单的二成员家族（Met31 和 Met32），该家族对于调节芽殖酵母中的硫代谢至关重要。酵母硫代谢受激活剂 Met4 转录调节。 Met4 缺乏 DNA 结合能力，依赖与 Met31 和 Met32（结合相同顺式调控元件的旁系同源蛋白）的相互作用来激活其靶标。尽管在没有蛋氨酸的情况下，Met31 和 Met32 对于生长来说是多余的，但研究表明，当 Met30（Met4 和 Met32 的负调节因子）不活跃时，Met32 比 Met31 具有更突出的作用。为了表征 Met31 和 Met32 在协调 Met4 激活转录中的不同作用，我们在缺乏 Met30 的情况下检测了缺乏 Met31 或 Met32 的菌株在 Met4 诱导时的转录。微阵列分析显示，与野生型和met31Δ细胞相比，met32Δ细胞中涉及硫酸盐同化和磺酸盐代谢的转录物显着减少。尽管存在这种差异，当存在 Met30 时，met31Δ 和 met32Δ 细胞都使用无机硫化合物和磺酸盐作为基本培养基中的唯一硫源。这种差异可以通过这两种条件下 Met31 与 Cbf1 依赖性启动子的不同结合来解释。在没有 Met30 的情况下，全基因组染色质免疫沉淀分析发现 Met32 结合了所有 Met4 结合的靶标，支持 Met32 作为 Met4 招募的主要平台。最后，Met31 和 Met32 水平受到差异调节，其中 Met32 水平模仿活性 Met4 的情况。当 Met30 缺失时，Met32 的这些不同特性可能有助于其在 Met4 激活转录中发挥突出作用。
To examine how target gene expression is coordinated among members of a transcription factor family, a simple two-member family (Met31 and Met32) that is essential for regulating sulfur metabolism in budding yeast is examined using both transcriptional and genome-wide binding arrays. Yeast sulfur metabolism is transcriptionally regulated by the activator Met4. Met4 lacks DNA-binding ability and relies on interactions with Met31 and Met32, paralogous proteins that bind the same cis-regulatory element, to activate its targets. Although Met31 and Met32 are redundant for growth in the absence of methionine, studies indicate that Met32 has a prominent role over Met31 when Met30, a negative regulator of Met4 and Met32, is inactive. To characterize different roles of Met31 and Met32 in coordinating Met4-activated transcription, we examined transcription in strains lacking either Met31 or Met32 upon Met4 induction in the absence of Met30. Microarray analysis revealed that transcripts involved in sulfate assimilation and sulfonate metabolism were dramatically decreased in met32Δ cells compared to its wild-type and met31Δ counterparts. Despite this difference, both met31Δ and met32Δ cells used inorganic sulfur compounds and sulfonates as sole sulfur sources in minimal media when Met30 was present. This discrepancy may be explained by differential binding of Met31 to Cbf1-dependent promoters between these two conditions. In the absence of Met30, genome-wide chromatin immunoprecipitation analyses found that Met32 bound all Met4-bound targets, supporting Met32 as the main platform for Met4 recruitment. Finally, Met31 and Met32 levels were differentially regulated, with Met32 levels mimicking the profile for active Met4. These different properties of Met32 likely contribute to its prominent role in Met4-activated transcription when Met30 is absent.