Related Experiment Videos
Regulation of C/EBP beta/NF-M activity by kinase oncogenes
G Twamley-Stein1, E Kowenz-Leutz, S Ansieau
1Max Delbrück Centrum for Molecular Biology (MDC), Berlin, Germany.
Abstract:
CAAT Enhancer Binding proteins (C/EBP) belong to a family of transcription factors which are implicated in a number of developmental and growth regulatory processes. One member of this family known as C/EBP beta (called NF-M in the chicken system) is particularly important in myelomonocytic cells because it is targeted by kinases and collaborates with the Myb oncoprotein to induce the expression of myeloid specific genes. Experiments dissecting the structure of NF-M suggest that it is a repressed transcription factor. Using the yeast two-hybrid system we showed that a negative regulatory domain masks the transactivation domain. Examination of NF-M mutants suggests that kinase (proto-) oncogenes uncover the concealed transcriptional activity by phosphorylation of the negative regulatory domain.
Insights
CAAT Enhancer Binding proteins (C/EBP) beta, a transcription factor, is repressed until kinases phosphorylate its negative regulatory domain. This uncovers its transcriptional activity, crucial for myeloid gene expression.
Area of Science:
- Molecular Biology
- Cellular Biology
- Oncology
Background:
- CAAT Enhancer Binding proteins (C/EBP) are transcription factors involved in development and growth.
- C/EBP beta (NF-M) is vital in myelomonocytic cells, targeted by kinases, and collaborates with Myb oncoprotein.
- C/EBP beta is implicated in myeloid-specific gene expression.
Purpose of the Study:
- To investigate the regulatory mechanisms of C/EBP beta's transcriptional activity.
- To understand how kinase activity influences C/EBP beta function.
- To elucidate the role of C/EBP beta in myeloid cell gene regulation.
Main Methods:
- Yeast two-hybrid system to analyze protein interactions.
- Mutagenesis studies to dissect C/EBP beta structure and function.
- Biochemical assays to examine phosphorylation effects.
Main Results:
- C/EBP beta functions as a repressed transcription factor.
- A negative regulatory domain masks the transactivation domain of C/EBP beta.
- Phosphorylation of the negative regulatory domain by kinases (proto-oncogenes) reveals transcriptional activity.
Conclusions:
- Kinase-mediated phosphorylation is a key mechanism for activating C/EBP beta.
- This activation is essential for the induction of myeloid-specific genes.
- Understanding C/EBP beta regulation provides insights into myelomonocytic cell development and oncogenesis.