Identification Of Salt-induced Cis-elements In CMO Promoter And Separation Of Transcription Factors Interacting With The Cis-elements

Betaine is a non-toxic penetration of protective agents in plants. Its accumulation makes many important enzymes of metabolism keep activity under osmotic stress, and protect the normal growth of plants. Choline monooxygenase (CMO) is the key enzyme for betaine synthesis. CMO gene expression is regulated by upstream promoter and transcription factors. The interaction between transcription factors and promoter cis-acting elements promote the expression of genes downstream. In this paper, the salt-related cis-acting elements in CMO promoter and their binding transcription factors were studied, and transcriptional regulation mechanism of CMO gene was analyzed.This thesis finds salt-related cis-acting elements in CMO promoter by electrophoretic mobility shift assay(EMSA), and transcription factors binding to the cis-acting elements were isolated by yeast one-hybrid experiments. The main results are as follows:1. CMO promoter sequence (-267～+128 bp) were analyzed using Genomatix Online software. 11 abiotic stress-related cis-acting elements were found in this sequence. 4 cis-acting elements:MYB element, W-box, GT-box and Salt/drought responsive element, were selected for EMSA.2. 4 probes were designed using the selected cis-acting elements as the core sequence. The interaction between probes and nuclear proteins from Suaeda liaotungensis leaves was detected by EMSA, Blocking signals were found in 2 probes. It is concluded that MYB element and Salt/drought responsive element may be the salt-induced cis-acting elements in CMO promoter.3. Using the Salt/drought responsive element as bait, a transcription factor was isolated from the cDNA library of Suaeda liaotungensis by yeast one-hybrid experiments, It is a PAPA-1-like family protein / zinc finger (HIT) family protein.