title: Arabidopsis SHORT INTEGUMENTS 2 is a mitochondrial DAR GTPase.
abstract: The Arabidopsis short integuments 2-1 (sin2-1) mutant produces ovules with short integuments due to early cessation of cell division in these structures. SIN2 was isolated and encodes a putative GTPase sharing features found in the novel DAR GTPase family. DAR proteins share a signature DAR motif and a unique arrangement of the four conserved GTPase G motifs. We found that DAR GTPases are present in all examined prokaryotes and eukaryotes and that they have diversified into four paralogous lineages in higher eukaryotes. Eukaryotic members of the SIN2 clade of DAR GTPases have been found to localize to mitochondria and are related to eubacterial proteins that facilitate essential steps in biogenesis of the large ribosomal subunit. We propose a similar role for SIN2 in mitochondria. A sin2 insertional allele has ovule effects similar to sin2-1, but more pronounced pleiotropic effects on vegetative and floral development. The diverse developmental effects of the mitochondrial SIN2 GTPase support a mitochondrial role in the regulation of multiple developmental pathways.
authors.affiliation: Section of Molecular and Cellular Biology, University of California, Davis, California 95616, USA.
authors.forename: Theresa A
authors.initials: TA
authors.lastname: Hill
authors.forename: Jean
authors.initials: J
authors.lastname: Broadhvest
authors.forename: Robert K
authors.initials: RK
authors.lastname: Kuzoff
authors.forename: Charles S
authors.initials: CS
authors.lastname: Gasser
mesh_terms: D000409:Alanine / Q000737:chemistry; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000145:classification / Q000235:genetics / Q000502:physiology*; D001120:Arginine / Q000737:chemistry; D001224:Aspartic Acid / Q000737:chemistry; D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology; D020558:GTP Phosphohydrolases / Q000145:classification / Q000235:genetics / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D043244:Ribonuclease III / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D001224:Aspartic Acid; D001120:Arginine; C402383:DCL1 protein, Arabidopsis; D043244:Ribonuclease III; D020558:GTP Phosphohydrolases; C515837:SIN2 protein, Arabidopsis; D000409:Alanine