Document Detail


Mitochondrial DNA ligases of Trypanosoma brucei.
MedLine Citation:
PMID:  15821136     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The mitochondrial DNA of Trypanosoma brucei, termed kinetoplast DNA or kDNA, consists of thousands of minicircles and a small number of maxicircles catenated into a single network organized as a nucleoprotein disk at the base of the flagellum. Minicircles are replicated free of the network but still contain nicks and gaps after rejoining to the network. Covalent closure of remaining discontinuities in newly replicated minicircles after their rejoining to the network is delayed until all minicircles have been replicated. The DNA ligase involved in this terminal step in minicircle replication has not been identified. A search of kinetoplastid genome databases has identified two putative DNA ligase genes in tandem. These genes (LIG k alpha and LIG k beta) are highly diverged from mitochondrial and nuclear DNA ligase genes of higher eukaryotes. Expression of epitope-tagged versions of these genes shows that both LIG k alpha and LIG k beta are mitochondrial DNA ligases. Epitope-tagged LIG k alpha localizes throughout the kDNA, whereas LIG k beta shows an antipodal localization close to, but not overlapping, that of topoisomerase II, suggesting that these proteins may be contained in distinct structures or protein complexes. Knockdown of the LIG k alpha mRNA by RNA interference led to a cessation of the release of minicircles from the network and resulted in a reduction in size of the kDNA networks and rapid loss of the kDNA from the cell. Closely related pairs of mitochondrial DNA ligase genes were also identified in Leishmania major and Crithidia fasciculata.
Authors:
Nick Downey; Jane C Hines; Krishna M Sinha; Dan S Ray
Related Documents :
11549946 - A method to purify bacteria-containing phagosomes from infected macrophages.
17251196 - The accessory subunit b of dna polymerase gamma is required for mitochondrial replisome...
16453676 - Variable dna splicing sites of a mitochondrial intron: relationship to the senescence p...
11959146 - Clk-1 protein has dna binding activity specific to o(l) region of mitochondrial dna.
21671306 - Toxic effects of lead and nickel nitrate on rat liver chromatin components.
8302116 - Laryngeal verrucous carcinoma: a clinicopathologic study and detection of human papillo...
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Eukaryotic cell     Volume:  4     ISSN:  1535-9778     ISO Abbreviation:  Eukaryotic Cell     Publication Date:  2005 Apr 
Date Detail:
Created Date:  2005-04-11     Completed Date:  2005-08-30     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  101130731     Medline TA:  Eukaryot Cell     Country:  United States    
Other Details:
Languages:  eng     Pagination:  765-74     Citation Subset:  IM    
Affiliation:
Molecular Biology Institute and Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90095-1570, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Amino Acid Sequence
Animals
Cloning, Molecular
DNA Ligases / genetics,  metabolism*
DNA Topoisomerases, Type II / metabolism
DNA, Kinetoplast / genetics,  metabolism*
DNA, Mitochondrial / genetics*
DNA, Protozoan / genetics*
Databases as Topic
Genome
Mitochondria / enzymology*
Molecular Sequence Data
RNA Interference
RNA, Messenger / antagonists & inhibitors,  genetics,  metabolism
Sequence Homology, Amino Acid
Trypanosoma brucei brucei / enzymology,  genetics*,  ultrastructure
Grant Support
ID/Acronym/Agency:
AI-28687/AI/NIAID NIH HHS; CA-16042/CA/NCI NIH HHS; GM53254/GM/NIGMS NIH HHS
Chemical
Reg. No./Substance:
0/DNA, Kinetoplast; 0/DNA, Mitochondrial; 0/DNA, Protozoan; 0/RNA, Messenger; EC 5.99.1.3/DNA Topoisomerases, Type II; EC 6.5.1.-/DNA Ligases
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Pairwise knockdowns of cdc2-related kinases (CRKs) in Trypanosoma brucei identified the CRKs for G1/...
Next Document:  Intracellular role of adenylyl cyclase in regulation of lateral pseudopod formation during Dictyoste...