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SNF2beta-BRG1 is essential for the viability of F9 murine embryonal carcinoma cells
C Sumi-Ichinose1, H Ichinose, D Metzger
1Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Collège de France, Illkirch, CU de Strasbourg.
Abstract:
The yeast and animal SNF-SWI and related multiprotein complexes are thought to play an important role in processes, such as transcription factor binding to regulatory elements, which require nucleosome remodeling in order to relieve the repressing effect of packaging DNA in chromatin. There are two mammalian homologs of the yeast SNF2-SWI2 subunit protein, SNF2alpha-brm and SNF2beta-BRG1, and overexpression of either one of them has been shown to enhance transcriptional activation by glucocorticoid, estrogen, and retinoic acid (RA) receptors in transiently transfected cells. We have investigated here the function of SNF2beta-BRG1 in the RA receptor-retinoid X receptor-mediated transduction of the retinoid signal in F9 embryonal carcinoma (EC) cells which differentiate into endodermal-like cells upon RA treatment. The two SNF2beta-BRG1 alleles have been targeted by homologous recombination and subsequently disrupted by using a conditional Cre recombinase. We show that F9 EC cells inactivated on both SNF2beta alleles are not viable and that heterozygous mutant cells are affected in proliferation but not in RA-induced differentiation. Thus, in F9 EC cells, SNF2beta-BRG1 appears to play an essential role in basal processes involved in cell proliferation, in addition to its putative role in the activation of transcription mediated by nuclear receptors.
Insights
SNF2beta-BRG1 is crucial for cell proliferation in F9 embryonal carcinoma cells. While not essential for retinoic acid-induced differentiation, its absence leads to non-viable cells, highlighting its vital role in basic cellular functions.
Area of Science:
- Molecular Biology
- Cell Biology
- Epigenetics
Background:
- SNF-SWI complexes remodel chromatin, facilitating transcription factor binding.
- Mammalian homologs SNF2alpha-brm and SNF2beta-BRG1 enhance nuclear receptor-mediated transcription.
- Retinoic acid (RA) signaling induces differentiation in F9 embryonal carcinoma (EC) cells via RA and retinoid X receptors.
Purpose of the Study:
- To investigate the function of SNF2beta-BRG1 in RA receptor-mediated signaling in F9 EC cells.
- To determine the role of SNF2beta-BRG1 in RA-induced differentiation and cell proliferation.
Main Methods:
- Targeted disruption of both SNF2beta-BRG1 alleles using homologous recombination and Cre recombinase in F9 EC cells.
- Assessment of cell viability, proliferation, and RA-induced differentiation in wild-type, heterozygous, and homozygous SNF2beta-BRG1 mutant cells.
Main Results:
- Complete inactivation of SNF2beta-BRG1 alleles resulted in non-viable F9 EC cells.
- Heterozygous SNF2beta-BRG1 mutant cells exhibited impaired proliferation but normal RA-induced differentiation.
- SNF2beta-BRG1 is essential for basal cell proliferation processes.
Conclusions:
- SNF2beta-BRG1 plays a critical role in F9 EC cell proliferation.
- While SNF2beta-BRG1 may contribute to nuclear receptor-mediated transcription, its essential function in F9 EC cells lies in cell proliferation.