AtMYB21, a gene encoding a flower-specific transcription factor, is regulated by COP1.
Light is an important environmental signal that governs plant growth and development. One important light-signalling component involved in plant light responses is COP1. The pleiotropic phenotypes of the cop1 mutant suggest that COP1 regulates not only photomorphogenesis, but also other developmental processes. We investigated the role of COP1 by identifying genes that are regulated by COP1. We report that AtMYB21, a gene encoding a flower-specific transcription factor, is ectopically expressed in the cop1 mutant. Analysis shows that dark-grown transgenic seedlings expressing AtMYB21-GR fusion protein display some features of the cop1 mutant, including decreased hypocotyl cell expansion, open cotyledons in the dark, and seedling lethality in the presence of dexamethasone. Light-grown adult transgenic plants expressing AtMYB21 have shorter stems, smaller and narrower leaves, narrower petals, and malformed carpels. In addition, we show that AtMYB21 directly regulates two genes that are also expressed more abundantly in the cop1 mutant. The results indicate that COP1 is required to repress the AtMYB21 gene in seedlings, and the pleiotropic phenotypes shown in the cop1 mutant are due to the combination of misregulation of genuine light-signalling components and other tissue-specific factors.
Shin
Byongchul
B
Kumho Life and Environmental Science Laboratory, 1 Oryong-dong, Buk-gu, Gwangju 500-712 Korea.
Choi
Goh
G
Yi
Hankuil
H
Yang
Seungchan
S
Cho
Insook
I
Kim
Jonghyun
J
Lee
Seunghee
S
Paek
Nam-Chon
NC
Kim
Jae-Hong
JH
Song
Pill-Soon
PS
Choi
Giltsu
G
D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D003624:Darkness; D003907:Dexamethasone / Q000494:pharmacology; D005298:Fertility; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D005966:Glucuronidase / Q000096:biosynthesis; D018546:Hypocotyl / Q000235:genetics / Q000254:growth & development; D008027:Light; D009154:Mutation; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics*; D018547:Plant Stems / Q000235:genetics* / Q000254:growth & development; D030821:Plants, Genetically Modified; D011995:Recombination, Genetic; D012097:Repressor Proteins / Q000235:genetics; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics*; D044767:Ubiquitin-Protein Ligases
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D010940:Plant Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D003907:Dexamethasone; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases; D005966:Glucuronidase