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- Chahtane, Hicham, et al.
(författare)
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LEAFY activity is post-transcriptionally regulated by BLADE ON PETIOLE2 and CULLIN3 in Arabidopsis
- 2018
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Ingår i: New Phytologist. - : Wiley-Blackwell. - 0028-646X .- 1469-8137. ; 220:2, s. 579-592
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Tidskriftsartikel (refereegranskat)abstract
- The Arabidopsis LEAFY (LFY) transcription factor is a key regulator of floral meristem emergence and identity. LFY interacts genetically and physically with UNUSUAL FLORAL ORGANS, a substrate adaptor of CULLIN1-RING ubiquitin ligase complexes (CRL1). The functionally redundant genes BLADE ON PETIOLE1 (BOP1) and -2 (BOP2) are potential candidates to regulate LFY activity and have recently been shown to be substrate adaptors of CULLIN3 (CUL3)-RING ubiquitin ligases (CRL3). We tested the hypothesis that LFY activity is controlled by BOPs and CUL3s in plants and that LFY is a substrate for ubiquitination by BOP-containing CRL3 complexes. When constitutively expressed, LFY activity is fully dependent on BOP2 as well as on CUL3A and B to regulate target genes such as APETALA1 and to induce ectopic flower formation. We also show that LFY and BOP2 proteins interact physically and that LFY-dependent ubiquitinated species are produced invitro in a reconstituted cell-free CRL3 system in the presence of LFY, BOP2 and CUL3. This new post-translational regulation of LFY activity by CRL3 complexes makes it a unique transcription factor subjected to a positive dual regulation by both CRL1 and CRL3 complexes and suggests a novel mechanism for promoting flower development.
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- Fougeres, Chloe, et al.
(författare)
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Search for Na-22 in novae supported by a novel method for measuring femtosecond nuclear lifetimes
- 2023
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Classical novae are thermonuclear explosions in stellar binary systems, and important sources of Al-26 and Na-22. While ? rays from the decay of the former radioisotope have been observed throughout the Galaxy, Na-22 remains untraceable. Its half-life (2.6 yr) would allow the observation of its 1.275 MeV ?-ray line from a cosmic source. However, the prediction of such an observation requires good knowledge of its nucleosynthesis. The Na-22(p, ?)Mg-23 reaction remains the only source of large uncertainty about the amount of Na-22 ejected. Its rate is dominated by a single resonance on the short-lived state at 7785.0(7) keV in Mg-23. Here, we propose a combined analysis of particle-particle correlations and velocity-difference profiles to measure femtosecond nuclear lifetimes. The application of this method to the study of the Mg-23 states, places strong limits on the amount of Na-22 produced in novae and constrains its detectability with future space-borne observatories. The authors report a particle-particle correlation and velocity-difference profile method to measure nuclear lifetime. The results obtained for excited states of 23Mg are used to constrain the production of 22Na in the astrophysical novae explosions.
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