Variation in expression of the Haemophilus influenzae HMW adhesins: A prokaryotic system reminiscent of eukaryotes
AUTOR(ES)
Dawid, Suzanne
FONTE
The National Academy of Sciences
RESUMO
Expression of a number of eukaryotic genes is regulated by long stretches of tandem repeats located within the 5′ untranslated region of the particular gene. In this study, we describe a regulatory system in Haemophilus influenzae with striking similarities to those found in eukaryotes. We show that expression of the HMW1 and HMW2 adhesins varies based on the number of 7-bp tandem repeats in the hmw1A and hmw2A promoters. The repeats lie between two separate transcription initiation sites and exert a repressive effect, such that increases in repeat number result in step-wise decreases in levels of specific mRNA and protein production and vice versa. The range of expression of HMW1 and HMW2 varies between very weak and very strong, with a series of gradations in between. Variation in the number of repeats in the hmw1A and hmw2A promoters occurs in individual colonies passaged in vitro, in an animal model of infection, and during natural infection in humans. This system of regulation is unique in prokaryotes and likely enhances the pathogenicity of the organism by increasing adaptive potential.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=15353Documentos Relacionados
- Mapping of Binding Domains of Nontypeable Haemophilus influenzae HMW1 and HMW2 Adhesins
- Evolutionary and Functional Relationships among the Nontypeable Haemophilus influenzae HMW Family of Adhesins†‡
- Prevalence and Distribution of the hmw and hia Genes and the HMW and Hia Adhesins among Genetically Diverse Strains of Nontypeable Haemophilus influenzae
- Prevalence of the hifBC, hmw1A, hmw2A, hmwC, and hia Genes in Haemophilus influenzae Isolates
- Identification of New hmwA Alleles from Nontypeable Haemophilus influenzae