Maskell D J, Szabo M J, Butler P D, Williams A E, Moxon E R
Molecular Infectious Diseases Group, John Radcliffe Hospital, Headington, Oxford, UK.
Mol Microbiol. 1991 May;5(5):1013-22. doi: 10.1111/j.1365-2958.1991.tb01874.x.
A chromosomal locus, lic3, one of several involved in lipopolysaccharide (LPS) biosynthesis by Haemophilus influenzae, was cloned and its DNA sequence determined. lic3 comprises four closely apposed open reading frames (ORFs). ORF1 includes tandem repeats of the tetramer CAAT and two start codons out of frame with each other are found upstream of the repeats. ORF1 encodes a protein with no known homologues. ORF2 encodes the UDP-galactose-4-epimerase (galE) gene. ORF3 encodes a hydrophobic protein with no known homologues. ORF4 encodes the adenylate kinase (adk) gene. A deletion/insertion mutation lacking the 3' end of ORF1, all of galE, and the 5' end of ORF3 was constructed in the parent Hib strain (RM7004). These mutants had a galE phenotype, as evidenced by galactose sensitivity, altered LPS when grown in the absence of exogenous galactose, and reduced virulence in infant rats.
一个染色体位点lic3，是流感嗜血杆菌参与脂多糖（LPS）生物合成的几个位点之一，已被克隆并测定了其DNA序列。lic3由四个紧密相邻的开放阅读框（ORF）组成。ORF1包含四聚体CAAT的串联重复序列，并且在重复序列上游发现了两个彼此移码的起始密码子。ORF1编码一种没有已知同源物的蛋白质。ORF2编码UDP-半乳糖-4-表异构酶（galE）基因。ORF3编码一种没有已知同源物的疏水蛋白。ORF4编码腺苷酸激酶（adk）基因。在亲本b型流感嗜血杆菌菌株（RM7004）中构建了一个缺失/插入突变体，该突变体缺失ORF1的3'末端、整个galE以及ORF3的5'末端。这些突变体具有galE表型，表现为对半乳糖敏感、在无外源半乳糖生长时LPS发生改变以及在幼鼠中的毒力降低。
