title: Centrin1 is required for organelle segregation and cytokinesis in Trypanosoma brucei.
abstract: Centrin is a calcium-binding centrosome/basal body-associated protein involved in duplication and segregation of these organelles in eukaryotes. We had shown that disruption of one of the centrin genes (centrin1) in Leishmania amastigotes resulted in failure of both basal body duplication and cytokinesis. Here, we undertook to define the role of centrin1 (TbCen1) in the duplication and segregation of basal body and its associated organelles kinetoplast and Golgi, as well as its role in cytokinesis of the procyclic form of Trypanosoma brucei by depleting its protein using RNA inhibition methodology. TbCen1-depleted cells showed significant reduction in growth compared with control cells. Morphological analysis of these cells showed they were large and pleomorphic with multiple detached flagella. Both immunofluorescence assays using organelle-specific antibodies and electron microscopic analysis showed that TbCen1-deficient cells contained multiple basal bodies, kinetoplasts, Golgi, and nuclei. These multiple organelles were, however, closely clustered together, indicating duplication without segregation in the absence of centrin. This failure in organelle segregation may be the likely cause of inhibition of cytokinesis, suggesting for the first time a new and unique role for centrin in the segregation of organelles without affecting their multiplication in the procyclic form of T. brucei.
authors.affiliation: Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA.
authors.forename: Angamuthu
authors.initials: A
authors.lastname: Selvapandiyan
authors.forename: Praveen
authors.initials: P
authors.lastname: Kumar
authors.forename: James C
authors.initials: JC
authors.lastname: Morris
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Salisbury
authors.forename: Ching C
authors.initials: CC
authors.lastname: Wang
authors.forename: Hira L
authors.initials: HL
authors.lastname: Nakhasi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D048749:Cytokinesis; D016054:DNA, Protozoan / Q000032:analysis; D005407:Flagella / Q000378:metabolism; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D008954:Models, Biological; D008969:Molecular Sequence Data; D015388:Organelles / Q000378:metabolism*; D010271:Parasites / Q000166:cytology / Q000254:growth & development; D021381:Protein Transport; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D013379:Substrate Specificity; D009626:Terminology as Topic; D014346:Trypanosoma brucei brucei / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D016054:DNA, Protozoan; D015800:Protozoan Proteins; D012333:RNA, Messenger