UBIQUITOUS EXPRESSION OF THE 43-KDA AND 44-KDA FORMS OF TRANSCRIPTION FACTOR USF IN MAMMALIAN-CELLS
UBIQUITOUS EXPRESSION OF THE 43-KDA AND 44-KDA FORMS OF TRANSCRIPTION FACTOR USF IN MAMMALIAN-CELLS
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DOI：
10.1093/nar/22.3.427
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发表时间：
1994-02-11
影响因子：
14.9
通讯作者：
SAWADOGO, M
中科院分区：
文献类型：
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作者：
SIRITO, M;LIN, Q;SAWADOGO, M
USF是一种螺旋-环-螺旋转录因子，与Myc一样，识别DNA结合基序CACGTG。最初通过生化分析在HeLa细胞中鉴定出两种不同形式的USF，其表观分子量分别为43,000和44,000。43-kDa USF的克隆首次被鉴定，但仅报道了人类44-kDa USF的部分克隆（USF2或FIP）。在这里，我们描述了来自小鼠细胞的44 kda USF的完整cDNA。对该克隆的分析表明，不同的USF家族成员在n端氨基酸序列上有很大的差异，而其二聚体和dna结合域具有高度的保守性。有趣的是，44 kda USF cdna的3'非编码区在人和小鼠之间表现出不同寻常的保守程度。体外转录/翻译实验表明该区域可能在翻译调控中起作用。44-kDa USF信息的不同剪接形式在小鼠和人类中都存在。通过Northern blot和凝胶阻滞实验检测USF的组织和细胞类型分布，发现虽然43- kda和44-kDa的USF物种的表达普遍存在，但在不同的细胞中发现不同比例的USF同源和异源二聚体。
USF is a helix-loop-helix transcription factor that, like Myc, recognizes the DNA binding motif CACGTG. Two different forms of USF, characterized by apparent molecular weights of 43,000 and 44,000, were originally identified in HeLa cells by biochemical analysis. Clones for the 43-kDa USF were first characterized, but only partial clones for the human 44-kDa USF (USF2, or FIP) have been reported. Here we describe a complete cDNA for the 44-kDa USF from murine cells. Analysis of this clone has revealed that the various USF family members are quite divergent in their N-terminal amino acid sequences, while a high degree of conservation characterizes their dimerization and DNA-binding domains. Interestingly, the 3' noncoding region of the 44-kDa USF cDNAs displayed an unusual degree of conservation between human and mouse. In vitro transcription/translation experiments indicated a possible role for this region in translational regulation. Alternative splicing forms of the 44-kDa USF messages exist in both mouse and human. Examination of the tissue and cell-type distribution of USF by Northern blot and gel retardation assays revealed that while expression of both the 43- and 44-kDa USF species is ubiquitous, different ratios of USF homo- and heterodimers are found in different cells.