S Phase-Specific Proteolytic Cleavage Is Required To Activate Stable DNA Binding by the CDP/Cut Homeodomain Protein
AUTOR(ES)
Moon, Nam Sung
FONTE
American Society for Microbiology
RESUMO
The CCAAT displacement protein (CDP), the homologue of the Drosophila melanogaster Cut protein, contains four DNA binding domains that function in pairs. Cooperation between Cut repeat 3 and the Cut homeodomain allows stable DNA binding to the ATCGAT motif, an activity previously shown to be upregulated in S phase. Here we showed that the full-length CDP/Cut protein is incapable of stable DNA binding and that the ATCGAT binding activity present in cells involves a 110-kDa carboxy-terminal peptide of CDP/Cut. A vector expressing CDP/Cut with Myc and hemagglutinin epitope tags at either end generated N- and C-terminal products of 90 and 110 kDa, suggesting that proteolytic cleavage was involved. In vivo pulse/chase labeling experiments confirmed that the 110-kDa protein was derived from the full-length CDP/Cut protein. Proteolytic processing was weak or not detectable in G0 and G1 but increased in populations of cells enriched in S phase, and the appearance of the 110-kDa protein coincided with the increase in ATCGAT DNA binding. Interestingly, the amino-truncated and the full-length CDP/Cut isoforms exhibited different transcriptional properties in a reporter assay. We conclude that proteolytic processing of CDP/Cut at the G1/S transition generates a CDP/Cut isoform with distinct DNA binding and transcriptional activities. These findings, together with the cleavage of the Scc1 protein at mitosis, suggest that site-specific proteolysis may play an important role in the regulation of cell cycle progression.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=87367Documentos Relacionados
- The Differentiation-Specific Factor CDP/Cut Represses Transcription and Replication of Human Papillomaviruses through a Conserved Silencing Element
- Circadian phase-specific degradation of the F-box protein ZTL is mediated by the proteasome
- CDP/cut is the DNA-binding subunit of histone gene transcription factor HiNF-D: a mechanism for gene regulation at the G1/S phase cell cycle transition point independent of transcription factor E2F.
- C/EBPɛ mediates myeloid differentiation and is regulated by the CCAAT displacement protein (CDP/cut)
- S phase-specific synthesis of dihydrofolate reductase in Chinese hamster ovary cells.