Antagonistic Controls of Chromatin and mRNA Start Site Selection by Tup Family Corepressors and the CCAAT-Binding Factor

Abstract

The Tup family corepressors contribute to critical cellular responses, such as the stress response and differentiation, presumably by inducing repressive chromatin, though the precise repression mechanism remains to be elucidated. The Schizosaccharomyces pombe fission yeast Tup family corepressors Tup11 and Tup12 (Tup11/12), which are orthologs of Tup1 in Saccharomyces cerevisiae budding yeast and Groucho in Drosophila, negatively control chromatin and the transcriptional activity of some stress-responsive genes. Here, we demonstrate that Tup11/12 repress transcription of a gluconeogenesis gene, fbp1⁺, by three distinct mechanisms. First, Tup11/12 inhibit chromatin remodeling in the fbp1⁺ promoter region where the Atf1 and Rst2 transcriptional activators bind. Second, they repress the formation of an open chromatin configuration at the fbp1⁺ TATA box. Third, they repress mRNA transcription per se by regulating basic transcription factors. These inhibitory actions of Tup11/12 are antagonized by three different types of transcriptional activators: CREB/ATF-type Atf1, C₂H₂ zinc finger-type Rst2, and CBF/NF-Y-type Php5 proteins. We also found that impaired chromatin remodeling and fbp1⁺mRNA transcription in php5Δ strains are rescued by the double deletions of tup11⁺ and tup12⁺, although the distribution of the transcription start sites becomes broader than that in wild-type cells. These data reveal a new mechanism of precise determination of the mRNA start site by Tup family corepressors and CBF/NF-Y proteins.

Supplemental material for this article may be found at http://dx.doi.org/10.1128/MCB.00924-14.

ACKNOWLEDGMENTS

We thank the members of the K. Hirota laboratory for their help and support. Special thanks go to M. Nakagawa for technical support.

Financial support was provided in part by the Uehara Memorial Foundation, the Naito Foundation, and a Grant-in-Aid for Scientific Research on Innovative Areas (chromatin structure, dynamics, and function) (to K.H.), grants from the Japan Society for the Promotion of Science (23114003, 21241046, and 26291018) to K.O., and a Grant-in-Aid for JSPS Fellows (13J08245) to N.T. This work was also supported by the Platform for Dynamic Approaches to Living System from the Ministry of Education, Culture, Sports, Science and Technology of Japan.