S phase activation of the histone H2B promoter by OCA-S, a coactivator complex that contains GAPDH as a key component.
We have isolated and functionally characterized a multicomponent Oct-1 coactivator, OCA-S which is essential for S phase-dependent histone H2B transcription. The p38 component of OCA-S binds directly to Oct-1, exhibits potent transactivation potential, is selectively recruited to the H2B promoter in S phase, and is essential for S phase-specific H2B transcription in vivo and in vitro. Surprisingly, p38 represents a nuclear form of glyceraldehyde-3-phosphate dehydrogenase, and binding to Oct-1, as well as OCA-S function, is stimulated by NAD(+) but inhibited by NADH. OCA-S also interacts with NPAT, a cyclin E/cdk2 substrate that is broadly involved in histone gene transcription. These studies thus link the H2B transcriptional machinery to cell cycle regulators, and possibly to cellular metabolic state (redox status), and set the stage for studies of the underlying mechanisms and the basis for coordinated histone gene expression and coupling to DNA replication.
Pubmed ID: 12887926 RIS Download
Amino Acid Sequence | Carrier Proteins | Cell Cycle Proteins | Cell Nucleus | DNA-Binding Proteins | Glyceraldehyde 3-Phosphate Dehydrogenase (NADP+) | HeLa Cells | Histones | Host Cell Factor C1 | Humans | Molecular Sequence Data | Nuclear Proteins | Octamer Transcription Factor-1 | Promoter Regions, Genetic | Proteins | RNA, Small Interfering | S Phase | Sequence Homology, Amino Acid | Trans-Activators | Transcription Factors | Transcription, Genetic | Transcriptional Activation | Tumor Cells, Cultured | p38 Mitogen-Activated Protein Kinases