title: [A new model of translational control of gene expression in polycistron++ of AB5 entrerotoxin].
abstract: The expression level of the B subunit gene of cholera toxin (ctx) and E. coli heat labile toxin (ltx) is five to seven times more than that of A subunit gene. In these studies, a 80 basepair translation regulation element was found located in the structure gene of A gene of both toxin operon which consists of three translation initiation region. Site-directed mutation of the initiation codon of TIR3 resulted in the 9 time decrease of the expression of the downstream cistron which was translational coupled with A gene. The results indicated that translation from the internal of A gene and translation coupling are responsible for the differential expression level of the A and B gene of AB5 enterotoxin.
authors.affiliation: Institute of Biotechnology, Academy of Military Medical Sciences, Beijing, China.
authors.forename: C
authors.initials: C
authors.lastname: Cao
authors.forename: P
authors.initials: P
authors.lastname: Li
authors.forename: P
authors.initials: P
authors.lastname: Wang
authors.forename: J Z
authors.initials: JZ
authors.lastname: Li
authors.forename: C H
authors.initials: CH
authors.lastname: Shi
authors.forename: Q J
authors.initials: QJ
authors.lastname: Ma
mesh_terms: D001427:Bacterial Toxins / Q000235:genetics*; D001483:Base Sequence; D002772:Cholera Toxin / Q000235:genetics*; D004768:Enterotoxins / Q000235:genetics*; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009876:Operon; D014176:Protein Biosynthesis
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D002772:Cholera Toxin; C027538:heat-labile enterotoxin, E coli