TY - JOUR
T1 - EFL GTPase in Cryptomonads and the Distribution of EFL and EF-1α in Chromalveolates
AU - Gile, Gillian H.
AU - Patron, Nicola J.
AU - Keeling, Patrick J.
N1 - Funding Information:
This work was supported by a grant (227301) from the Natural Sciences and Engineering Research Council of Canada. Guillardia theta, R. salina, O. marina and K. micrum EST sequencing was supported by the Protist EST Program of Genome Canada/Genome Atlantic. Sequencing of the P. marinus genome is supported by the NSF/USDA-CSREES Microbial Sequencing Program (Award NSF/USDA ♯ 0333240). We thank Uwe Maier for sharing sequences from an independent G. theta EST project prior to publication, C. Slamovits for help with O. marina EST data, and G. Noble for technical assistance. PJK is a Fellow of the Canadian Institute for Advanced Research and a New Investigator of the Canadian Institutes for Health Research and the Michael Smith Foundation for Health Research.
PY - 2006/10/24
Y1 - 2006/10/24
N2 - EFL (EF-like protein) is a member of the GTPase superfamily that includes several translation factors. Because it has only been found in a few eukaryotic lineages and its presence correlates with the absence of the related core translation factor EF-1α, its distribution is hypothesized to be the result of lateral gene transfer and replacement of EF-1α. In one supergroup of eukaryotes, the chromalveolates, two major lineages were found to contain EFL (dinoflagellates and haptophytes), while the others encode EF-1α (apicomplexans, ciliates, heterokonts and cryptomonads). For each of these groups, this distribution was deduced from whole genome sequence or expressed sequence tag (EST) data from several species, with the exception of cryptomonads from which only a single EF-1α PCR product from one species was known. By sequencing ESTs from two cryptomonads, Guillardia theta and Rhodomonas salina, and searching for all GTPase translation factors, we revealed that EFL is present in both species, but, contrary to expectations, we found EF-1α in neither. On balance, we suggest the previously reported EF-1α from Rhodomonas salina is likely an artefact of contamination. We also identified EFL in EST data from two members of the dinoflagellate lineage, Karlodinium micrum and Oxyrrhis marina, and from an ongoing genomic sequence project from a third, Perkinsus marinus. Karlodinium micrum is a symbiotic pairing of two lineages that would have both had EFL (a dinoflagellate and a haptophyte), but only the dinoflagellate gene remains. Oxyrrhis marina and Perkinsus marinus are early diverging sister-groups to dinoflagellates, and together show that EFL originated early in this lineage. Phylogenetic analysis confirmed that these genes are all EFL homologues, and showed that cryptomonad genes are not detectably related to EFL from other chromalveolates, which collectively form several distinct groups. The known distribution of EFL now includes a third group of chromalveolates, cryptomonads. Of the six major subgroups of chromalveolates, EFL is found in half and EF-1α in the other half, and none as yet unambiguously possess both genes. Phylogenetic analysis indicates EFL likely arose early within each subgroup where it is found, but suggests it may have originated multiple times within chromalveolates as a whole.
AB - EFL (EF-like protein) is a member of the GTPase superfamily that includes several translation factors. Because it has only been found in a few eukaryotic lineages and its presence correlates with the absence of the related core translation factor EF-1α, its distribution is hypothesized to be the result of lateral gene transfer and replacement of EF-1α. In one supergroup of eukaryotes, the chromalveolates, two major lineages were found to contain EFL (dinoflagellates and haptophytes), while the others encode EF-1α (apicomplexans, ciliates, heterokonts and cryptomonads). For each of these groups, this distribution was deduced from whole genome sequence or expressed sequence tag (EST) data from several species, with the exception of cryptomonads from which only a single EF-1α PCR product from one species was known. By sequencing ESTs from two cryptomonads, Guillardia theta and Rhodomonas salina, and searching for all GTPase translation factors, we revealed that EFL is present in both species, but, contrary to expectations, we found EF-1α in neither. On balance, we suggest the previously reported EF-1α from Rhodomonas salina is likely an artefact of contamination. We also identified EFL in EST data from two members of the dinoflagellate lineage, Karlodinium micrum and Oxyrrhis marina, and from an ongoing genomic sequence project from a third, Perkinsus marinus. Karlodinium micrum is a symbiotic pairing of two lineages that would have both had EFL (a dinoflagellate and a haptophyte), but only the dinoflagellate gene remains. Oxyrrhis marina and Perkinsus marinus are early diverging sister-groups to dinoflagellates, and together show that EFL originated early in this lineage. Phylogenetic analysis confirmed that these genes are all EFL homologues, and showed that cryptomonad genes are not detectably related to EFL from other chromalveolates, which collectively form several distinct groups. The known distribution of EFL now includes a third group of chromalveolates, cryptomonads. Of the six major subgroups of chromalveolates, EFL is found in half and EF-1α in the other half, and none as yet unambiguously possess both genes. Phylogenetic analysis indicates EFL likely arose early within each subgroup where it is found, but suggests it may have originated multiple times within chromalveolates as a whole.
KW - Chromalveolates
KW - cryptomonads
KW - dinoflagellates
KW - lateral gene transfer
KW - translation factor
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U2 - 10.1016/j.protis.2006.06.002
DO - 10.1016/j.protis.2006.06.002
M3 - Article
C2 - 16904374
AN - SCOPUS:33749447132
SN - 1434-4610
VL - 157
SP - 435
EP - 444
JO - Protist
JF - Protist
IS - 4
ER -