The protein kinases AtMAP3Kepsilon1 and BnMAP3Kepsilon1 are functional homologues of S. pombe cdc7p and may be involved in cell division.
We identified an Arabidopsis thaliana gene, AtMAP3Kepsilon1, and a Brassica napus cDNA, BnMAP3Kepsilon1, encoding functional protein serine/threonine kinases closely related to cdc7p and Cdc15p from Schizosaccharomyces pombe and Saccharomyces cerevisiae, respectively. This is the first report of cdc7-related genes in non-fungal eukaryotes; no such genes have as yet been identified in Metazoans. The B. napus protein is able to partially complement a cdc7 loss of function mutation in S. pombe. RT-PCR and in situ hybridisation revealed that the A. thaliana and B. napus genes are expressed in both the sporophytic and the gametophytic tissues of the respective plant species and revealed further that expression is highest in dividing cells. Moreover, AtMAP3Kepsilon1 gene expression is cell cycle-regulated, with higher expression in G2-M phases. Our results strongly suggest that the plant cdc7p-related protein kinases are involved in a signal transduction pathway similar to the SIN pathway, which positively regulates cytokinesis in S. pombe.
Jouannic
S
S
Institut de Biotechnologie des Plantes, Laboratoire de Biologie du Développement des Plantes, Bâtiment 630, UMR CNRS 8618, Université de Paris-Sud, F-91405 Orsay Cedex, France.
Champion
A
A
Segui-Simarro
J M
JM
Salimova
E
E
Picaud
A
A
Tregear
J
J
Testillano
P
P
Risueño
M C
MC
Simanis
V
V
Kreis
M
M
Henry
Y
Y
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D029681:Arabidopsis Proteins; D001937:Brassica / Q000201:enzymology / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division; D017343:Genes, Plant; D008969:Molecular Sequence Data; D010940:Plant Proteins; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid
D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D010940:Plant Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C489404:CDC7 protein, S cerevisiae; C489406:cdc7 protein, S pombe; D017346:Protein Serine-Threonine Kinases; C435708:MAP3Kepsilon1 protein, Arabidopsis