| 1. |
- Söfteland, John M., 1977, et al.
(author)
-
Longevity of anti-spike and anti-nucleocapsid antibodies after COVID-19 in solid organ transplant recipients compared to immunocompetent controls.
- 2022
-
In: American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons. - : Elsevier BV. - 1600-6143. ; 22:4, s. 1245-1252
-
Journal article (peer-reviewed)abstract
- Solid organ transplant recipients (SOTRs) are on lifelong immunosuppression, which may interfere with adaptive immunity to COVID-19. The data on dynamics and duration of antibody response in SOTRs are limited. This longitudinal study examined the longevity of both anti-spike (S)- and anti-nucleocapsid (N)-specific IgG-antibodies after COVID-19 in SOTRs compared to matched immunocompetent persons. SOTRs (n=65) were matched with controls (n=65) for COVID-19 disease severity, age, and sex in order of priority. Serum-IgG-antibodies against N- and S-antigens of SARS-CoV-2 were analyzed. At 1 and 9 months after COVID-19, anti-S-IgG detectability decreased from 91% to 82% in SOTRs versus 100% to 95% in controls, whereas the anti-N-IgG decreased from 63% to 29% in SOTRs versus 89% to 46% in controls. A matched paired analysis showed SOTRs having significantly lower levels of anti-N-IgG at all time points (1-month P=0.007, 3-months P<0.001, 6-months P=0.019 and 9-months P=0.021) but not anti-S-IgG at any time points. A mixed-model analysis confirmed these findings except for anti-S-IgG at one month (p=0.005) and identified severity score as the most important predictor of antibody response. SOTRs mount comparable S-specific, but not N-specific, antibody responses to SARS-CoV-2 infection compared to immunocompetent controls.
|
|
| 2. |
- Crocco, Carlos D, et al.
(author)
-
AtBBX21 and COP1 genetically interact in the regulation of shade avoidance.
- 2010
-
In: The Plant journal. - 1365-313X. ; 64:4, s. 551-62
-
Journal article (peer-reviewed)abstract
- Plants grown at high densities perceive the reduction in the ratio of red (R) to far-red (FR) light as a warning of competition. This light signal triggers morphological responses such as hypocotyl and stem elongation, and acceleration of flowering, which are known collectively as the shade-avoidance syndrome (SAS). Mutations in the photomorphogenic repressor COP1 suppress the SAS, but how COP1 modulates these responses is uncertain. We identified a new mutant with altered responses to natural shade, named lhus (long hypocotyl under shade). lhus seedlings have longer hypocotyls than wild-type under a low R:FR ratio, but not under sunlight or darkness. The lhus phenotype is due to a mutation affecting a B-box zinc finger transcription factor encoded by At1g75540, a gene previously reported as AtBBX21 that interacts with COP1 to control de-etiolation. Mutations in genes encoding other members of this protein family also result in impaired SAS regulation. Under short-term canopy shade, LHUS/BBX21 acts as positive regulator of SAS genes such as PAR1, HFR1, PIL1 and ATHB2. In contrast, global expression analysis of wild-type and lhus/bbx21 seedlings revealed that a large number of genes involved in hormonal signalling pathways are negatively regulated by LHUS/BBX21 in response to long-term canopy shade, and this observation fits well with the phenotype of lhus/bbx21 seedlings grown under a low R:FR ratio. Moreover, the bbx21 bbx22 double mutation restored the SAS in the cop1 background. We propose that LHUS/BBX21 and other B-box-containing proteins, such as BBX22, act downstream of COP1, and play a central role in early and long-term adjustment of the SAS in natural environments.
|
|
| 3. |
- Datta, Sourav, 1979, et al.
(author)
-
Arabidopsis CONSTANS-LIKE3 is a positive regulator of red light signaling and root growth.
- 2006
-
In: The Plant cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 18:1, s. 70-84
-
Journal article (peer-reviewed)abstract
- CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) is an E3 ubiquitin ligase that represses photomorphogenesis in the dark. Therefore, proteins interacting with COP1 could be important regulators of light-dependent development. Here, we identify CONSTANS-LIKE3 (COL3) as a novel interaction partner of COP1. A green fluorescent protein-COL3 fusion protein colocalizes with COP1 to nuclear speckles when transiently expressed in plant cells. This localization requires the B-box domains in COL3, indicating a novel function of this domain. A loss-of-function col3 mutant has longer hypocotyls in red light and in short days. Unlike constans, the col3 mutant flowers early and shows a reduced number of lateral branches in short days. The mutant also exhibits reduced formation of lateral roots. The col3 mutation partially suppresses the cop1 and deetiolated1 (det1) mutations in the dark, suggesting that COL3 acts downstream of both of these repressors. However, the col3 mutation exerts opposing effects on cop1 and det1 in terms of lateral roots and anthocyanin accumulation, suggesting that COL3 also has activities that are independent of COP1 and DET1. In conclusion, we have identified COL3 as a positive regulator of photomorphogenesis that acts downstream of COP1 but can promote lateral root development independently of COP1 and also function as a daylength-sensitive regulator of shoot branching.
|
|
| 4. |
- Datta, Sourav, 1979, et al.
(author)
-
LZF1/SALT TOLERANCE HOMOLOG3, an Arabidopsis B-Box Protein Involved in Light-Dependent Development and Gene Expression, Undergoes COP1-Mediated Ubiquitination.
- 2008
-
In: The Plant cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X.
-
Journal article (peer-reviewed)abstract
- B-box containing proteins play an important role in light signaling in plants. Here, we identify LIGHT-REGULATED ZINC FINGER1/SALT TOLERANCE HOMOLOG3 (STH3), a B-box encoding gene that genetically interacts with two key regulators of light signaling, ELONGATED HYPOCOTYL5 (HY5) and CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1). STH3 physically interacts with HY5 in vivo and shows a COP1-dependent localization to nuclear speckles when coexpressed with COP1 in plant cells. A T-DNA insertion mutant, sth3, is hyposensitive to high fluence blue, red, and far-red light and has elongated hypocotyls under short days. Analyses of double mutants between sth3, sth2, and hy5 suggest that they have partially overlapping functions. Interestingly, functional assays in protoplasts suggest that STH3 can activate transcription both independently and together with STH2 through the G-box promoter element. Furthermore, sth3 suppresses the cop1 hypocotyl phenotype in the dark as well as the anthocyanin accumulation in the light. Finally, COP1 ubiquitinates STH3 in vitro, suggesting that STH3 is regulated by COP1. In conclusion, we have identified STH3 as a positive regulator of photomorphogenesis acting in concert with STH2 and HY5, while also being a target of COP1-mediated ubiquitination.
|
|
| 5. |
|
|
| 6. |
- Datta, Sourav, 1979, et al.
(author)
-
STH2 has 2 B there: An insight into the role of B-box containing proteins in Arabidopsis
- 2008
-
In: Plant Signaling and Behavior. - 1559-2316. ; 3:8, s. 547-548
-
Journal article (other academic/artistic)abstract
- Recently we reported the identification of a novel B-box transcription factor SALT TOLERANCE HOMOLOG 2 (STH2) that interacts genetically with two key regulators of the light-signaling pathway, HY5 and COP1. We also provided phenotypic and genetic characterization of the sth2 mutant suggesting that STH2 plays a positive role in regulating photomorphogenesis both independently or together with HY5. Functional assays in protoplasts revealed that STH2 could act as a transcriptional activator. To our knowledge this is the first report of a B-box domain containing protein playing a direct role in activating transcription in plants. Here we discuss the possible position of STH2 in the transcriptional network and comment on the role of the B-box domain in plants.
|
|
| 7. |
- Gangappa, Sreeramaiah N, et al.
(author)
-
Molecular interactions of BBX24 and BBX25 with HYH, HY5 HOMOLOG, to modulate Arabidopsis seedling development
- 2013
-
In: Plant Signaling and Behavior. - : Informa UK Limited. - 1559-2324. ; 8:8
-
Journal article (peer-reviewed)abstract
- BBX24 and BBX25 are two important transcriptional regulators, which regulate seedling photomorphogenesis in Arabidopsis. Very recently, we have shown that BBX24 and BBX25 negatively regulate the expression of BBX22, reducing the function of HY5, by physically interacting with its bZIP domain.1 Furthermore, HY5 HOMOLOG, HYH, has been reported to heterodimerize with HY5 and enhances its photomorphogenic function in seedling de-etiolation by serving as coactivator.8 Here, we further report that BBX24 and BBX25 physically interact with HYH. The physical interactions of BBX24 and BBX25 with HYH could lead to depletion of HYH molecules from the active pool and, thus indirectly, reduce the function of HY5 in promoting photomorphogenesis. Hence, our results suggest another mode of regulation by which BBX24 and BBX25 exert their negative effects on HY5 indirectly through HYH for the fine-tuning of seedling photomorphogenesis. © 2013 Landes Bioscience.
|
|
| 8. |
- Gangappa, Sreeramaiah N, et al.
(author)
-
The Arabidopsis B-BOX Protein BBX25 Interacts with HY5, Negatively Regulating BBX22 Expression to Suppress Seedling Photomorphogenesis
- 2013
-
In: Plant Cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 25:4, s. 1243-1257
-
Journal article (peer-reviewed)abstract
- ELONGATED HYPOCOTYL5 (HY5) is a basic domain/leucine zipper (bZIP) transcription factor, central for the regulation of seedling photomorphogenesis. Here, we identified a B-BOX (BBX)–containing protein, BBX25/SALT TOLERANCE HOMOLOG, as an interacting partner of HY5, which has been previously found to physically interact with CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1). BBX25 physically interacts with HY5 both in vitro and in vivo. By physiological and genetic approaches, we showed that BBX25 is a negative regulator of seedling photomorphogenesis. BBX25 and its homolog BBX24 regulate deetiolation processes and hypocotyl shade avoidance response in an additive manner. Moreover, genetic relationships of bbx25 and bbx24 with hy5 and cop1 revealed that BBX25 and BBX24 additively enhance COP1 and suppress HY5 functions. BBX25 accumulates in a light-dependent manner and undergoes COP1-mediated degradation in dark and light conditions. Furthermore, a protoplast cotransfection assay showed that BBX24 and BBX25 repress BBX22 expression by interfering with HY5 transcriptional activity. As HY5 binds to the BBX22 promoter and promotes its expression, our results identify a direct mechanism through which the expression of BBX22 is regulated. We suggest that BBX25 and BBX24 function as transcriptional corepressors, probably by forming inactive heterodimers with HY5, downregulating BBX22 expression for the fine-tuning of light-mediated seedling development.
|
|
| 9. |
|
|
| 10. |
- Li, Feng, et al.
(author)
-
The B-Box Family Gene STO (BBX24) in Arabidopsis thaliana Regulates Flowering Time in Different Pathways
- 2014
-
In: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 9:2
-
Journal article (peer-reviewed)abstract
- Flowering at the appropriate time is crucial for reproductive success and is strongly influenced by various pathways such as photoperiod, circadian clock, FRIGIDA and vernalization. Although each separate pathway has been extensively studied, much less is known about the interactions between them. In this study we have investigated the relationship between the photoperiod/circadian clock gene and FRIGIDA/FLC by characterizing the function of the B-box STO gene family. STO has two B-box Zn-finger domains but lacks the CCT domain. Its expression is controlled by circadian rhythm and is affected by environmental factors and phytohormones. Loss and gain of function mutants show diversiform phenotypes from seed germination to flowering. The sto-1 mutant flowers later than the wild type (WT) under short day growth conditions, while over-expression of STO causes early flowering both in long and short days. STO over-expression not only reduces FLC expression level but it also activates FT and SOC1 expression. It also does not rely on the other B-box gene CO or change the circadian clock system to activate FT and SOC1. Furthermore, the STO activation of FT and SOC1 expression is independent of the repression of FLC; rather STO and FLC compete with each other to regulate downstream genes. Our results indicate that photoperiod and the circadian clock pathway gene STO can affect the key flowering time genes FLC and FT/SOC1 separately, and reveals a novel perspective to the mechanism of flowering regulation.
|
|
