期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1991
卷号：88
期号：5
页码：1968-1972
DOI：10.1073/pnas.88.5.1968
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We constructed a comprehensive cDNA library from HeLa cell mRNA in a vector that directs expression of the cDNA in Saccharomyces cerevisiae. We used this library to clone the human counterpart of the Sa. cerevisiae CCAAT-binding transcription factor, Hap2, by functional complementation of a hap2 mutation. The cDNA encoding the human Hap2 homolog encodes a protein of 257 amino acids that has a 62-amino acid carboxyl-terminal region 73% identical to the essential core region of Hap2. The amino terminus of the protein is highly enriched in glutamine residues, reminiscent of transcriptional activation domains of several other mammalian transcription factors. Analysis of human Hap2 expression reveals three major transcripts: a 4.1-kilobase species found in all cell types examined, a 7.0-kilobase species specific to B lymphocytes, and a 1.6-kilobase species that is expressed preferentially in HeLa cells and that likely corresponds to our cDNA clone. Thus, the human Hap2 homolog and related factors may play both a constitutive and cell type-specific role in gene expression. The general approach of cloning by complementation should allow the isolation of many human genes for which corresponding yeast mutations exist.
