4 research outputs found
The Arabidopsis SLEEPY1 Gene Encodes a Putative F-Box Subunit of an SCF E3 Ubiquitin Ligase
The Arabidopsis
SLY1
(
SLEEPY1
) gene positively regulates gibberellin (GA) signaling. Positional cloning of
SLY1
revealed that it encodes a putative F-box protein. This result suggests that SLY1 is the F-box subunit of an SCF E3 ubiquitin ligase that regulates GA responses. The DELLA domain protein RGA (repressor of
ga1-3
) is a repressor of GA response that appears to undergo GA-stimulated protein degradation. RGA is a potential substrate of SLY1, because
sly1
mutations cause a significant increase in RGA protein accumulation even after GA treatment. This result suggests SCF
SLY1
-targeted degradation of RGA through the 26S proteasome pathway. Further support for this model is provided by the observation that an
rga
null allele partially suppresses the
sly1-10
mutant phenotype. The predicted SLY1 amino acid sequence is highly conserved among plants, indicating a key role in GA response