Cloning and characterization of HUPF1, a human homolog of the Saccharomyces cerevisiae nonsense mRNA-reducing UPF1 protein
Cloning and characterization of HUPF1, a human homolog of the Saccharomyces cerevisiae nonsense mRNA-reducing UPF1 protein
复制标题
DOI：
10.1093/nar/25.4.814
复制
发表时间：
1997-02-15
影响因子：
14.9
通讯作者：
Jack, HM
中科院分区：
文献类型：
--
作者：
Applequist, SE;Selg, M;Jack, HM
在原核生物和真核生物中，大多数无义mRNAs的水平通常比相应的功能性mRNAs低，编码多肽的选择性降低无义mRNAs的基因到目前为止只在简单的真核生物中被鉴定出来。我们现在克隆了一个人的cDNAs，其推导的氨基酸序列与UPF1的同源性最高，UPF1是一种真正的酿酒酵母I族RNA解旋酶，需要加速降解无义mRNA.根据较短的酵母UPF1蛋白的全序列，除了NTPase和其他RNA解旋酶共识基序外，人蛋白与UPF1的总体同源性为51%，UPF1及其人类同源物也有其他I类RNA解旋酶所没有的相似的锌指基序，用人的cDNA探针进行Northern印迹分析发现，在几个人类细胞系中有两个转录本。最后，免疫荧光和Western印迹分析表明，人和小鼠的多肽，如酵母UPF1，在细胞质中表达，但不在细胞核中表达，因此我们鉴定了酵母UPF1的第一个哺乳动物同源物，这是一种调节无义mRNA水平的蛋白质，我们暂时将该蛋白命名为人HUPF1(表示UPF1的人类同源物)。
Levels of most nonsense mRNAs are normally reduced in prokaryotes and eukaryotes when compared with that of corresponding functional mRNAs, Genes encoding polypeptides that selectively reduce levels of nonsense mRNA have so far only been identified in simple eukaryotes, We have now cloned a human cDNA whose deduced amino acid sequence shows the highest degree of homology to that of UPF1, a bona fide Saccharomyces cerevisiae group I RNA helicase required for accelerated degradation of nonsense mRNA, Based on the total sequence of the shorter yeast UPF1 protein, the overall identity between the human protein and UPF1 is 51%, Besides NTPase and other RNA helicase Consensus motifs, UPF1 and its human homolog also share similar putative zinc finger motifs that are absent in other group I RNA helicases, Northern blot analysis with the human cDNA probe revealed two transcripts in several human cell lines. Further, antibodies raised against a synthetic peptide of the human polypeptide detected a single 130 kDa polypeptide on Western blots from human and mouse cells, Finally, immunofluorescence and Western blot analyses revealed that the human and mouse polypeptides, like yeast UPF1, are expressed in the cytoplasm, but not in the nucleus, We have thus identified the first mammalian homolog of yeast UPF1, a protein that regulates levels of nonsense mRNA, and we tentatively name this protein human HUPF1 (for human homolog of UPF1).