Host: The Japanese Society of Plant Physiologists
Pages 0265
Multiprotein bridging factor 1 (MBF1) is a transcriptional co-activator that mediates transcriptional activation in yeast and animals. Although Arabidopsis thaliana has three MBF1 genes, their functions remain unclear. In this study, AtMBF1 was fused to a strong transcriptional repression domain SRDX (AtMBF1-SRDX), and we tried to make transgenic Arabidopsis overexpressing this fusion protein. Since it is considered that AtMBF1-SRDX can exert dominant negative effect to endogenous AtMBF1s and prevent functions of AtMBF1-related transcription factors, it is expected to appear phenotypes based on functions of AtMBF1-related factors. Transgenic Arabidopsis overexpressing AtMBF1-SRDX (AtMBF1-SRDXOE) showed dwarf leaves phenotype, and its leaf cells were also tiny compared to those of wild type. We found ploidy level of leaves of AtMBF1-SRDXOE was reduced, and expression level of some negative regulators of endoreduplication was also increased in AtMBF1-SRDXOE. These results indicate that AtMBF1-SRDX suppresses endoreduplication in leaf cells through promoting expression of such negative regulators.
