Novel complexes of cyclin-dependent kinases and a cyclin-like protein from Arabidopsis thaliana with a function unrelated to cell division.
Although the majority of cyclin-dependent kinases (CDKs) play a key role in cell cycle progression, recent evidence has shown that CDKs are also implicated in transcription regulation. Here, we describe two Arabidopsis CDKs designated Arath;CDKC;1 and Arath; CDKC;2. These CDKs share a PITAIRE signature in the cyclin-binding domain and the structural characteristics of mammalian CDK9. Yeast two-hybrid screens and immunoprecipitation assays identified CDKC-interacting proteins with homology to the animal cyclin T/cyclin K group. We suggest that these Arabidopsis CDKCs may be part of a kinase complex similar to the animal positive transcription elongation factor b, whose activity is essential for transcription control. Expression studies showed that Arath; CDKC transcripts are mainly confined to epidermal tissues and are most abundant in flower tissues. No expression was detected in actively dividing Arabidopsis tissues, suggesting a role for the CDKC proteins in differentiated cells.
Barrôco
R M
RM
Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium.
De Veylder
L
L
Magyar
Z
Z
Engler
G
G
Inzé
D
D
Mironov
V
V
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000737:chemistry / Q000378:metabolism*; D002455:Cell Division; D018844:Cyclin-Dependent Kinases / Q000737:chemistry* / Q000378:metabolism*; D016213:Cyclins / Q000737:chemistry* / Q000378:metabolism*; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D016213:Cyclins; D012333:RNA, Messenger; D018844:Cyclin-Dependent Kinases