High impact information on RGL2

• These results suggest LEP is a positive regulator of GA-induced germination acting independently of RGL2 [1].
• Genetic analysis shows that the Arabidopsis DELLA proteins RGA and RGL2 jointly repress petal, stamen and anther development in GA-deficient plants, and that this function is enhanced by RGL1 activity [2].
• GA thus promotes Arabidopsis petal, stamen and anther development by opposing the function of the DELLA proteins RGA, RGL1 and RGL2 [2].
• Identification of the conserved serine/threonine residues important for gibberellin-sensitivity of Arabidopsis RGL2 protein [3].
• However, expression of GA 20-oxidase in BY2 cells expressing these mutant proteins is still responsive to GA, suggesting that the stabilization of RGL2 protein is not the only pathway for regulating its bioactivity [3].

Biological context of RGL2

• The relationship between expression of a negative regulator of GA signal transduction (RGL2) belonging to the DELLA gene family and repression of Arabidopsis seed germination has been studied (Lee S, Cheng H, King KE, Wang W, He Y, Hussain A, Lo J, Harberd NP, Peng J [2002] Genes and Development 16: 646-658) [4].

Associations of RGL2 with chemical compounds

• Transcription of the ABI3 and RGL2 genes is up-regulated by glucose [5].
• The inhibitory effect on seed germination seems to be accomplished via the activation of the ABA signalling pathway, through ABI3, and inactivation of the GA signalling pathway through RGL2 and SPY [5].

Regulatory relationships of RGL2

• It is possible that the RGL2 repressor of seed germination is inactivated by after-ripening of sly1 mutant seeds [6].

Other interactions of RGL2

• Previous studies provided evidence that RGL2 and possibly RGL1 control seed germination [7].
• We showed that RGL2 protein in imbibed seeds is rapidly degraded by GA treatment and that the F-box protein SLY1 is required for RGL2 degradation to occur [7].
• Three additional DELLA proteins RGL1, RGL2, and RGL3 are present in Arabidopsis [7].
• An alternative model places LEP downstream of RGL2 in the GA-signaling cascade [1].

Analytical, diagnostic and therapeutic context of RGL2

• RT-PCR shows that LEP transcript accumulates in wild-type seeds during imbibition and germination, and the transcript levels of REPRESSOR OF ga1-3-LIKE2 (RGL2), a negative regulator of GA signaling during germination, is unaffected in lep-1 [1].

References