Abstract
Rice lip19 encoding a 148 amino acids-bZIP protein has been isolated as one of low-temperature-induced genes. Its product, LIP19, seems to play a regulatory role in gene expression during cold stress, but none of its function has been uncovered. Currently we found that LIP19 lacks the common ability of bZIP transcription factors in tems of homodimerization and DNA binding. Thus, we searched for LIP19-interacting partner(s) and identified OsOBF1. So far, we have showed that (i) both LIP19 and OsOBF1 localize to nucleus, (ii) their spatial expression sites are same in rice leaf blades, and (iii) LIP19 directly interacts with OsOBF1 using in vitro pull down assay.
Here we show that DNA recognition sequence of LIP19-OsOBF1 heterodimer differs from that of OsOBF1 homodimer. We will also demonstrate LIP19-OsOBF1 interaction in vivo. Based on all the data obtained, we will discuss a role of LIP19 in a cold signaling pathway in rice.
