FINE-STRUCTURE ANALYSES OF THE DROSOPHILA AND SACCHAROMYCES HEAT-SHOCK FACTOR - HEAT-SHOCK ELEMENT INTERACTIONS
FINE-STRUCTURE ANALYSES OF THE DROSOPHILA AND SACCHAROMYCES HEAT-SHOCK FACTOR - HEAT-SHOCK ELEMENT INTERACTIONS
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DOI：
10.1093/nar/22.2.167
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发表时间：
1994-01-25
影响因子：
14.9
通讯作者：
LIS, JT
中科院分区：
文献类型：
--
作者：
FERNANDES, M;XIAO, H;LIS, JT
热休克基因通过热休克转录因子(HSF)与热休克元件(HSE)的结合而激活，热休克元件由5个碱基组成的单位NGaan排列成反向重复序列。在这里，我们研究了5-碱基单位与果蝇和酵母菌HSFs的相互作用。保守的中心三核苷酸GAA内的突变降低了两个HSF的相对结合亲和力。此外，位置1(N1)的碱基也影响结合，在该位置有强烈的A偏好。甲基化干扰最初表明HSF与小槽中的A1接触，但与主槽中紧邻的碱基G2相互作用。通过用肌苷取代A1，对这种明显突然的从次要到主要沟槽的转变的进一步表征表明，HSF与主要沟槽中的A1接触。我们解释了这一明显的矛盾，并提出HSF主要通过DNA螺旋主沟内的接触来识别HSE。最后，基于这些观察结果以及对基频和共识序列分配标准的重新评估，我们认为AGAAN序列更准确地代表了共识HSE基序。
Heat shock genes are activated by the binding of the heat shock transcription factor (HSF) to heat shock elements (HSEs), consisting of arrays of the 5-bp unit NGAAN arranged as inverted repeats. Here, we have investigated the interaction of the 5-bp unit with HSFs of Drosophila and Saccharomyces. Mutations within the conserved, central trinucleotide GAA reduce the relative binding affinity of both HSFs. In addition, the base at position 1 (N1) also influences binding, with a strong preference for an A at this position. Methylation interference initially indicated that HSF contacts A1 in the minor groove, but interacts with the immediately adjacent base G2 in the major groove. Further characterization of this apparently abrupt minor to major groove transition by substitution of A1 with an inosine, shows that HSF contacts A1 in the major groove. We offer an explanation for this apparent contradiction and propose that HSF recognizes the HSE primarily through contacts within the major groove of the DNA helix. Finally, based on these observations and a re-evaluation of the base frequencies and criteria for consensus sequence assignment, we propose that the sequence AGAAN more accurately represents the consensus HSE motif.