Common organization of gene clusters for production of different capsular polysaccharides (K antigens) in Escherichia coli.
Southern blot analysis of cloned K5- and K7-antigen genes, using DNA fragments from cloned K1 genes as radiolabeled probes, demonstrated that each K-antigen gene cluster is organized in a manner similar to that shown for the K1 antigen. That is, a central DNA segment unique for a given antigen type is flanked by DNA sequences that encode common functions for the management of intracellular polymer. This has been confirmed by transposon and deletion mutagenesis of plasmids carrying the K5 and K7 genes. We also describe a series of complementation experiments in which transport or postpolymerizational modification functions for one K antigen are used to complement mutations in the corresponding regions of a different K-antigen gene cluster. Thus, postpolymerizational modification of polysaccharide and transport of mature polysaccharide from the periplasmic space are common mechanisms and are independent of polysaccharide structure.
Roberts
I S
IS
Department of Microbiology, University of Leicester, United Kingdom.
Mountford
R
R
Hodge
R
R
Jann
K B
KB
Boulnois
G J
GJ
D000942:Antigens, Bacterial / Q000235:genetics*; D000954:Antigens, Surface / Q000235:genetics*; D004252:DNA Mutational Analysis; D004262:DNA Restriction Enzymes; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D012689:Sequence Homology, Nucleic Acid
D000942:Antigens, Bacterial; D000954:Antigens, Surface; D004251:DNA Transposable Elements; C030659:K antigens; D011135:Polysaccharides, Bacterial; D004262:DNA Restriction Enzymes