title: Eukaryotic GCP1 is a conserved mitochondrial protein required for progression of embryo development beyond the globular stage in Arabidopsis thaliana.
abstract: GCPs (glycoproteases) are members of the HSP70 (heat-shock protein 70)/actin ATPase superfamily that are highly conserved in taxonomically diverse species from bacteria to man, suggesting an essential physiological role. Although originally identified and annotated as putative endopeptidases, a proteolytic activity could not be confirmed for these proteins. Our survey of genome databases revealed that all eukaryotic organisms contain two GCP genes [called GCP1 and GCP2/Kae1 (kinase-associated endopeptidase 1)], whereas prokaryotes have only one, either of the GCP1- (Bacteria) or the GCP2/Kae1- (Archaea) type. GCP2/Kae1 is essential for telomere elongation and transcription of essential genes, although little is known about the localization, expression and physiological role of GCP1. In the present study on GCP1-type proteins from eukaryotic organisms we demonstrated that GCP1 is a mitochondrial protein in Homo sapiens [called here GCP1/OSGEPL1 (O-sialoglycoprotein endopeptidase)] and Arabidopsis thaliana, which is located/anchored to the mitochondrial inner membrane. Analysis of mRNA and protein levels revealed that the expression of GCP1/OSGEPL1 in A. thaliana and H. sapiens is tissue- and organ-specific and depends on the developmental stage, suggesting a more specialized function for this protein. We showed that homozygous A. thaliana GCP1 T-DNA (transferred DNA) insertion lines were embryonic lethal. Embryos in homozygous seeds were arrested at the globular stage and failed to undergo the transition into the heart stage. On the basis of these data we propose that the mitochondrial GCP1 is essential for embryonic development in plants.
authors.affiliation: Qiagen GmbH, Qiagen Strasse 1, DE-40724 Hilden, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Haussuehl
authors.forename: Pitter F
authors.initials: PF
authors.lastname: Huesgen
authors.forename: Marc
authors.initials: M
authors.lastname: Meier
authors.forename: Patrick
authors.initials: P
authors.lastname: Dessi
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Glaser
authors.forename: Jerzy
authors.initials: J
authors.lastname: Adamski
authors.forename: Iwona
authors.initials: I
authors.lastname: Adamska
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000196:embryology / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008297:Male; D008666:Metalloendopeptidases / Q000096:biosynthesis* / Q000235:genetics; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000096:biosynthesis* / Q000235:genetics; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000502:physiology; D011817:Rabbits; D036226:Seedlings / Q000196:embryology / Q000201:enzymology*; D013045:Species Specificity
chemical_list: D029681:Arabidopsis Proteins; C544491:GCP1 protein, Arabidopsis; C543705:GCP2 protein, Arabidopsis; D008869:Microtubule-Associated Proteins; D024101:Mitochondrial Proteins; D008666:Metalloendopeptidases; C070738:O-sialoglycoprotein endopeptidase