Identification of HiNF-P, a key activator of cell cycle-controlled histone H4 genes at the onset of S phase.
At the G(1)/S phase cell cycle transition, multiple histone genes are expressed to ensure that newly synthesized DNA is immediately packaged as chromatin. Here we have purified and functionally characterized the critical transcription factor HiNF-P, which is required for E2F-independent activation of the histone H4 multigene family. Using chromatin immunoprecipitation analysis and ligation-mediated PCR-assisted genomic sequencing, we show that HiNF-P interacts with conserved H4 cell cycle regulatory sequences in vivo. Antisense inhibition of HiNF-P reduces endogenous histone H4 gene expression. Furthermore, we find that HiNF-P utilizes NPAT/p220, a substrate of the cyclin E/cyclin-dependent kinase 2 (CDK2) kinase complex, as a key coactivator to enhance histone H4 gene transcription. The biological role of HiNF-P is reflected by impeded cell cycle progression into S phase upon antisense-mediated reduction of HiNF-P levels. Our results establish that HiNF-P is the ultimate link in a linear signaling pathway that is initiated with the growth factor-dependent induction of cyclin E/CDK2 kinase activity at the restriction point and culminates in the activation of histone H4 genes through HiNF-P at the G(1)/S phase transition.
Department of Cell Biology and Cancer Center, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA.
Partha
P
Mitra
Rong-Lin
RL
Xie
Ricardo
R
Medina
Hayk
H
Hovhannisyan
S Kaleem
SK
Zaidi
Yue
Y
Wei
J Wade
JW
Harper
Janet L
JL
Stein
André J
AJ
van Wijnen
Gary S
GS
Stein
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006657:Histones / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012097:Repressor Proteins; D016196:S Phase / Q000235:genetics* / Q000502:physiology*; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D016335:Zinc Fingers / Q000235:genetics
D018076:DNA, Complementary; C442219:HINFP protein, human; D006657:Histones; D011994:Recombinant Proteins; D012097:Repressor Proteins; D014157:Transcription Factors