Defects in glycopeptidolipid biosynthesis confer phage I3 resistance in Mycobacterium smegmatis.
Mycobacteriophages have played an important role in the development of genetic tools and diagnostics for pathogenic mycobacteria, including Mycobacterium tuberculosis. However, despite the isolation of numerous phages that infect mycobacteria, the mechanisms of mycobacteriophage infection remain poorly understood, and knowledge about phage receptors is minimal. In an effort to identify the receptor for phage I3, we screened a library of Mycobacterium smegmatis transposon mutants for phage-resistant strains. All four phage I3-resistant mutants isolated were found to have transposon insertions in genes located in a cluster involved in the biosynthesis of the cell-wall-associated glycopeptidolipid (GPL), and consequently the mutants did not synthesize GPLs. The loss of GPLs correlated specifically with phage I3 resistance, as all mutants retained sensitivity to two other mycobacteriophages: D29 and Bxz1. In order to define the minimal receptor for phage I3, we then tested the phage sensitivity of previously described GPL-deficient mutants of M. smegmatis that accumulate biosynthesis intermediates of GPLs. The results indicated that, while the removal of most sugar residues from the fatty acyl tetrapeptide (FATP) core of GPL did not affect sensitivity to phage I3, a single methylated rhamnose, transferred by the rhamnosyltransferase Gtf2 to the FATP core, was critical for phage binding.
Chen
Jiemin
J
School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
Kriakov
Jordan
J
Howard Hughes Medical Institute, Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
Singh
Albel
A
School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
Jacobs
William R
WR
Howard Hughes Medical Institute, Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
Besra
Gurdyal S
GS
School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
Bhatt
Apoorva
A
School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
D001483:Base Sequence; D004251:DNA Transposable Elements / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D005798:Genes, Bacterial; D006017:Glycolipids / Q000096:biosynthesis* / Q000737:chemistry; D006020:Glycopeptides / Q000096:biosynthesis* / Q000737:chemistry; D005810:Multigene Family; D016254:Mutagenesis, Insertional; D009160:Mycobacteriophages / Q000235:genetics / Q000472:pathogenicity*; D020102:Mycobacterium smegmatis / Q000235:genetics / Q000378:metabolism* / Q000821:virology*; D011991:Receptors, Virus / Q000378:metabolism
D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004279:DNA, Viral; D006017:Glycolipids; D006020:Glycopeptides; D011991:Receptors, Virus; C010762:peptidoglycolipids