title: The Arabidopsis HOBBIT gene encodes a CDC27 homolog that links the plant cell cycle to progression of cell differentiation.
abstract: In plant meristems, dividing cells interpret positional information and translate it into patterned cell differentiation. Here we report the molecular identification of the Arabidopsis HOBBIT gene that is required for cell division and cell differentiation in meristems. We show that it encodes a homolog of the CDC27 subunit of the anaphase-promoting complex (APC). HOBBIT partially complements a yeast nuc2/cdc27 mutant. Unlike other CDC27 homologs in Arabidopsis, its transcription is cell cycle regulated. Furthermore, hobbit mutants show a reduction in DR5 :: GUS auxin reporter gene expression and accumulate the AXR3/IAA17 repressor of auxin responses. HOBBIT activity may thus couple cell division to cell differentiation by regulating cell cycle progression in the meristem or by restricting the response to differentiation cues, such as auxin, to dividing cells.
mesh_terms: D000818:Animals; D064191:Apc3 Subunit, Anaphase-Promoting Complex-Cyclosome; D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D004258:DNA Polymerase III; D018744:DNA, Plant; D005656:Fungal Proteins / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D017930:Genes, Reporter; D005816:Genetic Complementation Test; D006801:Humans; D007210:Indoleacetic Acids / Q000378:metabolism; D018519:Meristem; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009687:Nuclear Proteins / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018520:Plant Shoots; D012568:Schizosaccharomyces; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid
chemical_list: D064191:Apc3 Subunit, Anaphase-Promoting Complex-Cyclosome; D029681:Arabidopsis Proteins; C577366:CDC27 protein, human; D018797:Cell Cycle Proteins; D018744:DNA, Plant; D005656:Fungal Proteins; C467333:HOBBIT protein, Arabidopsis; D007210:Indoleacetic Acids; C577354:NUC2 protein, S pombe; D009687:Nuclear Proteins; D010940:Plant Proteins; D029702:Schizosaccharomyces pombe Proteins; C513024:cdc27 protein, S pombe; D004258:DNA Polymerase III