The interactome of the histone gene regulatory factor HiNF-P suggests novel cell cycle related roles in transcriptional control and RNA processing.
HiNF-P is a recently identified histone H4 subtype specific transcriptional regulator that associates with the conserved cell cycle control element in the proximal promoter regions of histone H4 genes. HiNF-P interacts with the global histone gene regulator and direct cyclin E/CDK2 substrate p220(NPAT) to potently upregulate histone H4 gene transcription at the G1/S phase transition in response to cyclin E/CDK2 signaling. To gain insight into the function of HiNF-P in a broader cellular context, we performed a yeast two-hybrid screen to identify its novel interacting proteins. In this study, we detected 67 candidate HiNF-P interacting proteins of varying cellular functions. We have identified multiple RNA associated proteins, including the splicing co-factor SRm300. HiNF-P and SRm300 interact in yeast two-hybrid, co-immunoprecipitation, and co-immunofluorescence assays. Our screen also identified several gene regulators that associate with HiNF-P including THAP7. HiNF-P and THAP7 interact in mammalian cells and THAP7 abrogates HiNF-P/p220 mediated activation of histone H4 gene transcription, consistent with its known role as a transcriptional repressor. Finally, we identified several proliferation related proteins including Ki-67 and X transactivated protein 2 (XTP2) which may be functioning with HiNF-P in cell cycle regulation. The HiNF-P interactome indicates that HiNF-P is a multifunctional gene regulator with a large functional network and roles beyond cell cycle-dependent histone gene regulation.
Miele
Angela
A
Department of Cell Biology and Cancer Center, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
Medina
Ricardo
R
van Wijnen
Andre J
AJ
Stein
Gary S
GS
Stein
Janet L
JL
D002453:Cell Cycle; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D016601:RNA-Binding Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques
D002868:Chromosomal Proteins, Non-Histone; C442219:HINFP protein, human; D019394:Ki-67 Antigen; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; C414618:SRRM2 protein, human; C498974:THAP7 protein, human