Prokaryotic expression of Rex transcription regulator in Streptococcus suis 2 and in vitro binding assay / 中国人兽共患病学报

ABSTRACT

We cloned and prokaryoticly expressed the gene encoding Redox regulator(Rex)of Streptococcus suis serotype 2 and analyzed biological information and in vitro binding activity.The encoding Rex gene of SS2-1 strain was amplified by PCR with the designed primers,and then cloned into prokaryotic expression plasmid pET28a.The recombinant plasmid pET28a-Rex was transformed into E.coli BL21.After induced expression by IPTG,the Rex protein was obtained.The binding activity of Rex protein and DNA was analyzed by gel mobility shift assay (EMSA) in vitro.Purification of recombinant protein Rex was successfully expressed.The presence of NAD+ did not have major effect on mobility shift,but addition of NADH almost abolished such a binding activity.By in vitro binding assay,Rex was found to regulate the expression of Prex in response to NADH/NAD+ equilibrium.