Abstract
Multiprotein bridging factor 1 (MBF1) is known to be a transcriptional co-activator that mediates transcriptional activation by bridging between a transcription factor and a TATA-box binding protein in animals and yeast, and its amino acid sequence is highly conserved in eucaryote. Arabidopsis has three genes encoding MBF1 subtypes (AtMBF1a, 1b, and 1c, Tsuda et al., 2004). AtMBF1c is known to be involved in signal transduction pathways for various stress responses (Suzuki et al., 2005). However, any Arabidopsis protein that interacts with AtMBF1s has never been reported yet.
Since we didn,t get any information about biochemical function of AtMBF1s by the trial to observe phenotype associated with overexpression of these proteins in transgenic Arabidopsis, we decided to analyze transgenic plants that overexpress a chimeric AtMBF1. We found that abnormal phenotype observed in these transgenic lines is similar to that observed in photomorphogenetic mutant of Arabidopsis.
