A yeast and a human CCAAT-binding protein have heterologous subunits that are functionally interchangeable.
The S. cerevisiae HAP2 and HAP3 gene products have been shown to recognize CCAAT-containing transcription elements as a HAP2/HAP3 multisubunit heterologous complex, or heteromer. Recently, we have demonstrated that the human sequence-specific DNA-binding protein, CP1, also recognizes CCAAT-containing transcription elements as a heteromer. Mammalian cells contain at least three distinct CCAAT-binding proteins, all of which appear to be multisubunit complexes composed of heterologous subunits. One of these proteins, CP1, has DNA-binding properties that are virtually identical to the yeast HAP2/HAP3 complex. These two proteins bind to the same target sequences, make the same DNA contacts, and are affected in a similar manner by mutations in the CCAAT element. Most surprisingly, the subunits of CP1 and HAP2/HAP3 are functionally interchangeable. That is, the yeast/human hybrid complexes that are formed retain the ability to specifically recognize CCAAT elements.
Chodosh
L A
LA
Center for Cancer Research, Massachusetts Institute of Technology, Cambridge 02139.
Olesen
J
J
Hahn
S
S
Baldwin
A S
AS
Guarente
L
L
Sharp
P A
PA
D005075:Biological Evolution; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005796:Genes; D005800:Genes, Fungal; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D046911:Macromolecular Substances; D008745:Methylation; D009838:Oligodeoxyribonucleotides / Q000378:metabolism*; D010957:Plasmids; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D013045:Species Specificity
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D009838:Oligodeoxyribonucleotides