HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Wang, Y. Articles by Chen, C. Search for Related Content PubMed PubMed Citation Articles by Wang, Y. Articles by Chen, C. Agricola Articles by Wang, Y. Articles by Chen, C.

Genomic distribution and functions of uptake signal sequences in Actinobacillus actinomycetemcomitans

Ying Wang^1,

¹ Division of Primary Oral Health Care, University of Southern California School of Dentistry, 925 W 34th Street, Room 4107, Los Angeles, CA 90089-0641, USA
² Department of Microbiology and Immunology, University of Oklahoma, Oklahoma City, OK 73190, USA

Correspondence
Casey Chen
ccchen{at}usc.edu

Actinobacillus actinomycetemcomitans is naturally competent for transformation, with a transformation system similar to that of Haemophilus influenzae that preferentially takes up DNA bearing uptake signal sequences (USS) with the same 9-base USS core. This study examined the function of the extended 29-base USS, which comprises a highly conserved 1st region (containing the 9-base core) and 2nd and 3rd semi-conserved AT-rich regions, in transformation of A. actinomycetemcomitans. Transformation frequency was not affected by either location (in middle or at 5' end) or quantity (one or two) of USS in donor DNA. Relative transformation efficiencies (in comparison to the positive control) were 28–67 % for linear DNA with single-base mutations in the USS 1st region, and 47 % and 73 %, respectively, for linear DNA with USS that contained either a non-consensus 2nd or a non-consensus 3rd region. Plasmids with a stand-alone 1st or a stand-alone 2nd–3rd region exhibited 21 % and 6 % relative transformation efficiencies, respectively. It was also noted that A. actinomycetemcomitans and H. influenzae were similar in the frequencies and distribution patterns of USS in their genomes. In conclusion, all three regions of the extended 29-base USS are required for optimum transformation in A. actinomycetemcomitans.

Present address: Division of Infectious Diseases, Childrens Hospital Los Angeles, University of Southern California, CA 90027, USA.