Eukaryotic Cell doi:10.1128/EC.00282-06
Copyright (c) 2006, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.
Transmembrane molecules for phylogenetic analyses of pathogenic protists: Leishmania-specific informative sites in hydrophilic loops of trans-ER N-acetylglucosamine-1-phosphate transferase
Kayoko Waki,
Sujoy Dutta,
Debalina Ray,
Bala Krishna Kolli,
Shin-Ichiro Kawazu,
Chung-Ping Lin,
and
Kwang-Poo Chang*
Department of Microbiology/Immunology, Chicago Medical School, Rosalind Franklin University, North Chicago, IL, USA; National Research Center for Protozoan Diseases, Obihiro University, Hokkaido, Japan; and Department of Life Science, Tunghai University, Taichung, Taiwan
* To whom correspondence should be addressed. Email:
kwang-poo.chang{at}rosalindfranklin.edu.
 |
Abstract |
|---|
A sequence database was created for Leishmania N-acetylglucosamine-1-phosphate transferase gene (nagt) from 193 independent isolates. PCR products of this single-copy gene were analyzed for RFLP based on seven nagt sequences initially available. We subsequently sequenced 77 samples and found 19 new variants (genotypes). Alignment of all the 26 nagt sequences is gap-free, except for single codon-addition or -deletion. Phylogenetic analyses of the sequences allow grouping of the isolates into three subgenera, each consisting of recognized species complexes, i.e. subgenus Leishmania (L. amazonensis/mexicana, L. donovani/infantum, L. tropica, L. major, L. turanica/gerbilli), subgenus Viannia (L. braziliensis, L. panamensis) and one unclassified (L. enriettii). This hierarchy of grouping is also supported by sequence analyses of selected samples for additional single-copy genes present on different chromosomes. Intra-species divergence of nagt varies considerably with different species complexes. Interestingly, species complexes with less subspecies divergent are more widely distributed than those more divergent. The relevance of this to Leishmania evolutionary adaptation is discussed. Heterozygosity of subspecies variants contributes to intra-species diversity, which is prominent in L. tropica, but not in L. donovani/infantum. This disparity is thought to result from genetic recombination of the respective species at different time as a rare event during their predominantly clonal evolution. Phylogenetically useful sites of nagt are restricted largely to several extended hydrophilic loops predicted from hypothetical models of Leishmania NAGT as an ER transmembrane protein. In silico analyses of nagt from fungi and other protozoa further illustrate the potential value of this and, perhaps, other similar transmembrane molecules for phylogenetic analyses of single cell eukaryotes.
Previous Article | Next Article 
