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The role of a repetitive DNA motif (5′‐CAAT‐3′) in the variable expression of the Haemophilus influenzae lipopolysaccharide epitope αGal(1–4)βGal
Author(s) -
High Nicola J.,
Deadman Mary E.,
Moxon E. Richard
Publication year - 1993
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1993.tb01257.x
Subject(s) - biology , epitope , haemophilus influenzae , microbiology and biotechnology , phase variation , tandem repeat , antibody , genetics , gene , bacteria , phenotype , genome
Summary Haemophilus influenzae lipopolysaccharide (LPS) contains structures, defined by monoclonal antibodies, which undergo phase variation. This investigation reports the nucleotide sequence of lic2A , which is required for the expression of at least three phase‐variable LPS epitopes, one of which has the structure αGal(1–4)βGal. lic2A contains multiple tandem repeats of the tetramer 5′‐CAAT‐3′ Previous studies have correlated changes in the number of 5′‐CAAT‐3′ repeats with the phase‐variable expression of the αGal(1–4)βGal epitope. To obtain direct evidence for this, the 5′‐CAAT‐3′ repeat region from lic2A was amplified directly from immunostained colonies and sequenced. This demonstrated that the variable expression of LPS epitopes, including αGal(1–4)βGal, is in part directly dependent upon the number of copies of 5′‐CAAT‐3′ within lic2A.