NIH finding will accelerate study of chlamydial infections
11-Apr-2011 - WHAT: In a new study from the National Institute of Allergy and Infectious Diseases (NIAID), part
of the National Institutes of Health, scientists describe successfully mutating specific genes of Chlamydia bacteria, which cause the most
common sexually transmitted infection in the United States as well as a type of blindness common in developing nations. The procedure
they used will help advance scientists' understanding of how these bacteria cause human disease and expedite the development of new
strategies to prevent and control these infections.
The advance could end decades of frustration for scientists who until now have been unable to manipulate Chlamydia
genes in the laboratory, inhibiting research progress in the field.
Traditionally, gene manipulation involves directly introducing foreign DNA into bacteria. But Chlamydia bacteria
live inside cells where they are protected from foreign DNA by a series of cellular and bacterial membranes. Therefore, more complicated and
indirect approaches were applied to mutate Chlamydia genes.
The procedure, called Targeting Induced Local Lesions in Genomes (TILLING), has been used for years in plant
genetics but is new to bacterial genetics. In their study, NIAID scientists used TILLING to successfully change the function of a
specific Chlamydia gene. After creating a library of chemically mutated Chlamydia bacteria, they looked for mutations in a
specific target gene. The analysis yielded a mutant with a single genetic change in the target gene; that change both
inactivated the gene and greatly weakened the ability of the organism to survive in laboratory-grown human cells.
According to the study authors, TILLING may now be used to reveal the unknown function of hundreds of other Chlamydia genes in an effort
to better understand these infections and develop new ways to treat and prevent them.
Chlamydia diseases include both sexually transmitted infections, which can result in pelvic inflammatory disease that can cause infertility
in women, and trachoma, which can cause blindness and is common in developing nations. More than 1.2 million Chlamydia infections were
reported to the U.S. Centers for Disease Control and Prevention in 2009. The World Health Organization estimates that more than 140
million persons have trachoma in regions of Africa, the Middle East, Central and Southeast Asia and Latin America.
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ARTICLE: L Kari et al. Generation of targeted Chlamydia trachomatis null mutants. Proceedings of the National Academy of
Sciences. DOI: 10.1073/PNAS.1102229108 (2011).
WHO: Harlan Caldwell, Ph.D., chief of the Laboratory of Intracellular Parasites, is available to comment on this article.
CONTACT: To schedule interviews, please contact Ken Pekoc, (301) 402-1663, or kpekoc@niaid.nih.gov.
NIAID conducts and supports research-at NIH, throughout the United States, and worldwide-to study the causes of infectious and immune-mediated diseases, and
to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the
NIAID Web site at http://www.niaid.nih.gov .
About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department
of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes,
treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.
CONTACT:
Ken Pekoc
kpekoc@niaid.nih.gov 301-402-1663
NIH/National Institute of Allergy and Infectious Diseases
Source: EurekAlert!
http://www.eurekalert.org/pub_releases/2011-04/nioa-sfm041111.php
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