title: Bacterial orthologues indicate the malarial plastid gene ycf24 is essential.
abstract: ycf24 is a well conserved gene found in all major groups of bacteria, as well as on red algal plastid genomes and the vestigal plastid genome of apicomplexan pathogens like the malaria parasite Plasmodium falciparum (ORF470). Some database annotations describe Ycf24 as an ABC transporter subunit, but we find the level of significance is low. To investigate ycf24's function we disrupted it in the cyanobacterium Synechocystis sp., strain PCC6803 which has a multi-copy genome. This showed ycf24 is essential, partial loss producing a terminal phenotype of chlorosis, reduced cell size, loss of DNA, and a striking arrest in cytokinesis. Attempts to disrupt the single copy of ycf24 in E. coli failed to give stable transformants. When Ycf24 was over-expressed in E. coli as a soluble fusion protein, it localized mostly as a band on either side of the nucleoid and nucleoid partitioning was aberrant. We propose the relict plastid organelle of apicomplexans retains its capacity for protein synthesis because Ycf24 is essential.
authors.affiliation: National Institute for Medical Research, Mill Hill, London, UK.
authors.forename: A E
authors.initials: AE
authors.lastname: Law
authors.forename: C W
authors.initials: CW
authors.lastname: Mullineaux
authors.forename: E M
authors.initials: EM
authors.lastname: Hirst
authors.forename: J
authors.initials: J
authors.lastname: Saldanha
authors.forename: R J
authors.initials: RJ
authors.lastname: Wilson
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002453:Cell Cycle / Q000235:genetics; D000458:Cyanobacteria / Q000235:genetics; D004247:DNA / Q000032:analysis; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D058619:Maltose-Binding Proteins; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D009154:Mutation; D010963:Plasmodium falciparum / Q000235:genetics*; D018087:Plastids / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000461:Rhodophyta / Q000235:genetics; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D013489:Suppression, Genetic; D014169:Transformation, Bacterial / Q000235:genetics
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; C461599:maltose transport system, E coli; C424569:ycf24 protein, E coli; D004247:DNA