The sigma70 family of sigma factors.
The sigma70 family of sigma factors.
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DOI：
10.1186/gb-2003-4-1-203
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发表时间：
2003
期刊：
影响因子：
12.3
通讯作者：
Helmann JD
中科院分区：
文献类型：
--
作者：
Paget MS;Helmann JD
σ70因子家族的成员是RNA聚合酶全酶的组分，其将细菌或质体核心RNA聚合酶引导至转录起始点上游的特异性启动子元件。根据基因结构和功能，它们可以大致分为四大类。σ70因子家族成员是RNA聚合酶全酶的组成部分，其将细菌或质体核心RNA聚合酶引导至位于转录起始点上游10和35个碱基对的特异性启动子元件。σ70家族的成员也作为一些激活蛋白的接触点，如PhoB和λcl，并在起始过程中发挥作用。主要的σ因子是指数生长细胞中一般转录所必需的，与RNA聚合酶可逆地相关，并且可以被替代的σ因子所取代，所述替代的σ因子协调表达参与多种功能的基因，例如应激反应、形态发育和铁摄取。根据基因结构和功能，σ70家族的成员可以大致分为四个主要组。σ70家族成员的序列比对显示，它们有四个保守区域，尽管在区域2和4中发现了最高的保守性，其涉及与RNA聚合酶结合，识别启动子和分离DNA链（所谓的“DNA熔解”）。σ70因子的线性序列分为四个区域的划分在很大程度上得到了最近的结构数据的支持，这些数据表明主要σ因子具有三个稳定的域，包括区域2、3和4。此外，RNA聚合酶全酶的结构揭示了σ70的这些结构域分布在RNA聚合酶的一个面上。这些结构数据开始阐明σ因子在转录起始中的机制作用。
Members of the σ70 family of sigma factors are components of the RNA polymerase holoenzyme that direct bacterial or plastid core RNA polymerase to specific promoter elements upstream of the transcription-initiation points. They can broadly be divided into four main groups on the basis of gene structure and function. Members of the σ70 family of sigma factors are components of the RNA polymerase holoenzyme that direct bacterial or plastid core RNA polymerase to specific promoter elements that are situated 10 and 35 base-pairs upstream of transcription-initiation points. Members of the σ70 family also function as contact points for some activator proteins, such as PhoB and λcl, and play a role in the initiation process itself. The primary σ factor, which is essential for general transcription in exponentially growing cells, is reversibly associated with RNA polymerase and can be replaced by alternative σ factors that co-ordinately express genes involved in diverse functions, such as stress responses, morphological development and iron uptake. On the basis of gene structure and function, members of the σ70 family can broadly be divided into four main groups. Sequence alignments of the σ70 family members reveal that they have four conserved regions, although the highest conservation is found in regions 2 and 4, which are involved in binding to RNA polymerase, recognizing promoters and separating DNA strands (so-called 'DNA melting'). The division of the linear sequence of σ70 factors into four regions is largely supported by recent structural data indicating that primary σ factors have three stable domains that incorporate regions 2, 3 and 4. Furthermore, structures of the RNA polymerase holoenzyme have revealed that these domains of σ70 are spread out across one face of RNA polymerase. These structural data are starting to illuminate the mechanistic role of σ factors in transcription initiation.
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影响因子：
64.8
作者：
BURGESS, RR;TRAVERS, AA;BAUTZ, EKF
通讯作者：
BAUTZ, EKF
DOI：
10.1073/pnas.94.26.14948
发表时间：
1997-12-23
影响因子：
11.1
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通讯作者：
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16
作者：
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影响因子：
64.5
作者：
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通讯作者：
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