COP1, an Arabidopsis regulatory gene, encodes a protein with both a zinc-binding motif and a G beta homologous domain.
Plant seedling development is capable of following 1 of 2 distinct morphogenic pathways: skotomorphogenesis in darkness and photomorphogenesis in light. Dark-grown Arabidopsis seedlings with recessive mutations at the constitutively photomorphogenic (COP1) locus indicate that the wild-type COP1 protein represses photomorphogenesis in darkness and that light reverses this repressive activity. Using a T-DNA-tagged mutant, we have cloned the COP1 locus. The amino-terminal half of the encoded protein contains a conserved zinc-binding motif, whereas the carboxyl-terminal half contains a domain homologous to the WD-40 repeat motif of G beta proteins. The presence of both a putative DNA-binding motif and a G protein-related domain in a single polypeptide suggests that COP1 may be the first of a new class of regulatory molecules. This novel structure could endow COP1 with the capacity to function as a negative transcriptional regulator capable of direct interaction with components of the G protein signaling pathway.
Deng
X W
XW
University of California, Berkeley, United States Department of Agriculture Plant Gene Expression Center, Albany 94710.
Matsui
M
M
Wei
N
N
Wagner
D
D
Chu
A M
AM
Feldmann
K A
KA
Quail
P H
PH
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D001483:Base Sequence; D002454:Cell Differentiation; D003001:Cloning, Molecular; D016384:Consensus Sequence; D019204:GTP-Binding Proteins / Q000235:genetics*; D015870:Gene Expression / Q000528:radiation effects; D017343:Genes, Plant; D005809:Genes, Regulator; D008027:Light; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D016415:Sequence Alignment; D016335:Zinc Fingers
D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D019204:GTP-Binding Proteins