Unveiling the signal transduction of phytohormone abscisic acid （ABA） and its regulatory mechanisms is critical for developing the strategies toward improving plant responses to stressful environments. ABA signaling...Unveiling the signal transduction of phytohormone abscisic acid （ABA） and its regulatory mechanisms is critical for developing the strategies toward improving plant responses to stressful environments. ABA signaling is perceived and mediated by multiple PYR/PYL receptors, whose post-translational modifications, especially phosphorylation, remain largely unknown. In this study, we demonstrate thatArabidopsis ELl-like （AEL） protein, a casein kinase that regulates various physiological processes, phosphorylate PYR/PYLs to promote their ubiquitination and degradation, resulting in suppressed ABA responses. Arabidopsis ael triple mutants display hypersensitive responses to ABA treatment, which is consistent with the suppressed degradation of PYR/PYL proteins. PYR/PYLs are phosphorylated in vivo and mutation of the conserved AEL phosphorylation sites results in reduced phosphorylation, ubiquitination, and degradation of PYR/PYLs, and hence enhanced ABA responses. Taken together, these results demonstrate that AEL-mediated phosphorylation plays crucial roles in regulating the stability and function of PYR/ PYLs, providing significant insights into the post-translational regulation of PYR/PYL receptors and ABA signaling.展开更多
Homeobox transcription factors are involved in various aspects of plant development, including maintenance of the biosynthesis and signaling pathways of different hormones. However, few direct targets of homeobox prot...Homeobox transcription factors are involved in various aspects of plant development, including maintenance of the biosynthesis and signaling pathways of different hormones. However, few direct targets of homeobox proteins have been identified. We here show that overexpression of rice homeobox gene HOXla resulted in enhanced gibberellin （GA） response, indicating a positive effect of HOXla in GA signaling. HOXla is induced by GA and encodes a homeobox transcription factor with transcription repression activity. In addition, HOXla suppresses the transcription of early flowering1 （EL1）, a negative regulator of GA signaling, and further electrophoretic mobility shift assay and chromatin immunoprecipitation analysis revealed that HOXla directly bound to the promoter region of EL1 to suppress its expression and stimulate GA signaling. These results demonstrate that HOXla functions as a positive regulator of GA signaling by suppressing EL1, providing informative hints on the study of GA signaling.展开更多
Background: Androgens have been implicated in androgenic alopecia as evidenced by the increased cutaneous expression of androgen receptor (AR), 5α-reductase, and decreased aromatase. Abnormalities of the AR-signal tr...Background: Androgens have been implicated in androgenic alopecia as evidenced by the increased cutaneous expression of androgen receptor (AR), 5α-reductase, and decreased aromatase. Abnormalities of the AR-signal transduction pathway probably participate in the development of androgenic alopecia. ARA70/ELE1 is an AR coactivator with two isoforms, one full-length form (ARA70α/ELE1α), and a n internally deleted form (ARA70β/ELE1β). We decided to examine the cutaneous expression of both isoforms in male androgenic alopecia. Methods: Formalin-fixe d, paraffin-embedded tissue sections from seven subjects with androgenic alopec ia with matched punch biopsies from non-balding and balding areas were examined by in situ hybridization. Results: Expression of at least one of the two probes for ARA70/ELE1 was present in all phases of the hair-growth cycle in all epith elial hair structures except for the inner root sheath. The dermal papilla and h air bulb expressed only the short (β) but not the long (α) form of ARA70/ELE1. In situ labeling for ARA70β/ELE1βwas weaker in the dermal papilla of balding recipient areas than those from donor ones. Conclusions: Our data further suppor t that the hair growth is regulated by androgens. The differential expression pa ttern of ARA70/ELE1 suggests that this key androgen receptor coactivator is invo lved in androgenic alopecia.展开更多
文摘Unveiling the signal transduction of phytohormone abscisic acid （ABA） and its regulatory mechanisms is critical for developing the strategies toward improving plant responses to stressful environments. ABA signaling is perceived and mediated by multiple PYR/PYL receptors, whose post-translational modifications, especially phosphorylation, remain largely unknown. In this study, we demonstrate thatArabidopsis ELl-like （AEL） protein, a casein kinase that regulates various physiological processes, phosphorylate PYR/PYLs to promote their ubiquitination and degradation, resulting in suppressed ABA responses. Arabidopsis ael triple mutants display hypersensitive responses to ABA treatment, which is consistent with the suppressed degradation of PYR/PYL proteins. PYR/PYLs are phosphorylated in vivo and mutation of the conserved AEL phosphorylation sites results in reduced phosphorylation, ubiquitination, and degradation of PYR/PYLs, and hence enhanced ABA responses. Taken together, these results demonstrate that AEL-mediated phosphorylation plays crucial roles in regulating the stability and function of PYR/ PYLs, providing significant insights into the post-translational regulation of PYR/PYL receptors and ABA signaling.
基金supported by the Chinese Academy of Sciences (KSCX2-YW-N-058, KSCX2-YW-N-016)the National Natural Science Foundation of China (30570992)a project (2008ZX08009-003) from the Ministry of Agriculture of China for Transgenic Research
文摘Homeobox transcription factors are involved in various aspects of plant development, including maintenance of the biosynthesis and signaling pathways of different hormones. However, few direct targets of homeobox proteins have been identified. We here show that overexpression of rice homeobox gene HOXla resulted in enhanced gibberellin （GA） response, indicating a positive effect of HOXla in GA signaling. HOXla is induced by GA and encodes a homeobox transcription factor with transcription repression activity. In addition, HOXla suppresses the transcription of early flowering1 （EL1）, a negative regulator of GA signaling, and further electrophoretic mobility shift assay and chromatin immunoprecipitation analysis revealed that HOXla directly bound to the promoter region of EL1 to suppress its expression and stimulate GA signaling. These results demonstrate that HOXla functions as a positive regulator of GA signaling by suppressing EL1, providing informative hints on the study of GA signaling.
文摘Background: Androgens have been implicated in androgenic alopecia as evidenced by the increased cutaneous expression of androgen receptor (AR), 5α-reductase, and decreased aromatase. Abnormalities of the AR-signal transduction pathway probably participate in the development of androgenic alopecia. ARA70/ELE1 is an AR coactivator with two isoforms, one full-length form (ARA70α/ELE1α), and a n internally deleted form (ARA70β/ELE1β). We decided to examine the cutaneous expression of both isoforms in male androgenic alopecia. Methods: Formalin-fixe d, paraffin-embedded tissue sections from seven subjects with androgenic alopec ia with matched punch biopsies from non-balding and balding areas were examined by in situ hybridization. Results: Expression of at least one of the two probes for ARA70/ELE1 was present in all phases of the hair-growth cycle in all epith elial hair structures except for the inner root sheath. The dermal papilla and h air bulb expressed only the short (β) but not the long (α) form of ARA70/ELE1. In situ labeling for ARA70β/ELE1βwas weaker in the dermal papilla of balding recipient areas than those from donor ones. Conclusions: Our data further suppor t that the hair growth is regulated by androgens. The differential expression pa ttern of ARA70/ELE1 suggests that this key androgen receptor coactivator is invo lved in androgenic alopecia.
