Ciz1, a p21 cip1/Waf1-interacting zinc finger protein and DNA replication factor, is a novel molecular partner for human enhancer of rudimentary homolog.
Enhancer of rudimentary homolog (Drosophila) (ERH) is a small, highly conserved, nuclear protein with a unique three-dimensional structure, whose gene has been identified in animals, plants and protists, but not in fungi. Involvement of ERH in fundamental processes such as regulation of pyrimidine metabolism, cell cycle progression, transcription and cell growth control has been suggested. Here, employing a yeast two-hybrid system, a glutathione S-transferase pull-down assay and tandem MS, we demonstrate that Ciz1 is a bona fide interactor of human ERH. Ciz1 is a nuclear zinc finger protein interacting with p21(Cip1/Waf1), a universal inhibitor of cyclin-dependent kinases, and is a DNA replication factor. The region of Ciz1 necessary for the interaction with ERH spans residues 531-644, encompassing its first zinc finger motif. This region overlaps the p21(Cip1/Waf1)-binding site, suggesting that the interaction with ERH could block the binding of p21(Cip1/Waf1) by Ciz1 in the cell. When ERH and Ciz1 are coexpressed in HeLa cells, Ciz1 recruits ERH to DNA replication foci.
Lukasik
Anna
A
Institute of Biochemistry, University of Warsaw, Miecznikowa 1, Warsaw, Poland.
Uniewicz
Katarzyna A
KA
Kulis
Marta
M
Kozlowski
Piotr
P
D000595:Amino Acid Sequence; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism*; D017931:DNA Primers; D004261:DNA Replication; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D053719:Tandem Mass Spectrometry; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D016335:Zinc Fingers
D018797:Cell Cycle Proteins; C400423:Ciz1 protein, human; D017931:DNA Primers; C484495:ERH protein, human; D009687:Nuclear Proteins; D014157:Transcription Factors