Molecular weight abnormalities of the CTCF transcription factor: CTCF migrates aberrantly in SDS-PAGE and the size of the expressed protein is affected by the UTRs and sequences within the coding region of the CTCF gene
Molecular weight abnormalities of the CTCF transcription factor: CTCF migrates aberrantly in SDS-PAGE and the size of the expressed protein is affected by the UTRs and sequences within the coding region of the CTCF gene
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DOI：
10.1093/nar/25.3.466
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发表时间：
1997-02-01
影响因子：
14.9
通讯作者：
Goodwin, GH
中科院分区：
文献类型：
--
作者：
Klenova, EM;Nicolas, RH;Goodwin, GH
CTCF属于锌指转录因子家族，与c-myc的启动子区域结合，CTCF在物种间高度保守，广泛存在于细胞核内。在SDS-PAGE上，内源性CTCF以130 kDa(CTCF-130)蛋白的形式迁移，而CTCF的开放阅读框架(ORF)只编码82 kDa的蛋白(CTCF-82)。本研究对这一现象进行了研究，并通过质谱分析表明，这是由于CTCF蛋白的异常迁移性所致。另一个悖论是，我们的原始cDNA由ORF和3‘-非翻译区(3’-UTR)组成，产生一种表观分子量为70 kDa的蛋白质(CTCF-70)。这种矛盾已经被发现是CTCF基因编码区内的UTRs和序列的影响导致CTCF-130的C-末端截断，潜在的衰减器已经被识别并点突变，这恢复了CTCF蛋白的电泳迁移率到130 kDa，CTCF-70，本身的异常迁移的CTCF N末端，在一些细胞类型中也被检测到，因此可能有一些生物学意义，特别是CTCF-70干扰CTCF-130的正常功能，增强CTCF-130诱导的COS6细胞的反式激活。文中还讨论了CTCF-70的作用机理及其他可能的作用。
CTCF belongs to the Zn finger transcription factors family and binds to the promoter region of c-myc, CTCF is highly conserved between species, ubiquitous and localised in nuclei, The endogenous CTCF migrates as a 130 kDa (CTCF-130) protein on SDS-PAGE, however, the open reading frame (ORF) of the CTCF cDNA encodes only a 82 kDa protein (CTCF-82), In the present study we investigate this phenomenon and show with mass-spectra analysis that this occurs due to aberrant mobility of the CTCF protein, Another paradox is that our original cDNA, composed of the ORF and 3'-untranslated region (3'-UTR), produces a protein with the apparent molecular weight of 70 kDa (CTCF-70). This paradox has been found to be an effect of the UTRs and sequences within the coding region of the CTCF gene resulting in C-terminal truncation of CTCF-130, The potential attenuator has been identified and point-mutated, This restored the electrophoretic mobility of the CTCF protein to 130 kDa, CTCF-70, the aberrantly migrating CTCF N-terminus per se, is also detected in some cell types and therefore may have some biological implications, In particular, CTCF-70 interferes with CTCF-130 normal function, enhancing transactivation induced by CTCF-130 in COS6 cells. The mechanism of CTCF-70 action and other possible functions of CTCF-70 are discussed.