MicroProtein-mediated recruitment of CONSTANS into a TOPLESS trimeric complex represses flowering in Arabidopsis

MicroProteins are short, single domain proteins that act by sequestering larger, multi-domain proteins into non-functional complexes. MicroProteins have been identified in plants and animals, where they are mostly involved in the regulation of developmental processes. Here we show that two Arabidopsis thaliana microProteins, miP1a and miP1b, physically interact with CONSTANS (CO) a potent regulator of flowering time. The miP1a/b-type microProteins evolved in dicotyledonous plants and have an additional carboxy-terminal PF(V/L)FL motif. This motif enables miP1a/b microProteins to interact with TOPLESS/TOPLESS-RELATED (TPL/TPR) proteins. Interaction of CO with miP1a/b/TPL causes late flowering due to a failure in the induction of FLOWERING LOCUS T (FT) expression under inductive long day conditions. Both miP1a and miP1b are expressed in vascular tissue, where CO and FT are active. Genetically, miP1a/b act upstream of CO thus our findings unravel a novel layer of flowering time regulation via microProtein-inhibition

Meta-analysis of Arabidopsis KANADI1 direct target genes identifies basic growth-promoting module acting upstream of hormonal signaling pathways

An intricate network of antagonistically acting transcription factors mediates the formation of a flat leaf lamina of Arabidopsis (Arabidopsis thaliana) plants. In this context, members of the class III homeodomain leucine zipper (HD-ZIPIII) transcription factor family specify the adaxial domain (future upper side) of the leaf, while antagonistically acting KANADI transcription factors determine the abaxial domain (future lower side). Here, we used a messenger RNA sequencing approach to identify genes regulated by KANADI1 (KAN1) and subsequently performed a meta-analysis combining our data sets with published genome-wide data sets. Our analysis revealed that KAN1 acts upstream of several genes encoding auxin biosynthetic enzymes. When exposed to shade, we found three YUCCA genes, YUC2, YUC5, and YUC8, to be transcriptionally up-regulated, which correlates with an increase in the levels of free auxin. When ectopically expressed, KAN1 is able to transcriptionally repress these three YUC genes and thereby block shade-induced auxin biosynthesis. Consequently, KAN1 is able to strongly suppress shade-avoidance responses. Taken together, we hypothesize that HD-ZIPIII/KAN form the basis of a basic growth-promoting module. Hypocotyl extension in the shade and outgrowth of new leaves both involve auxin synthesis and signaling, which are under the direct control of HD-ZIPIII/KAN.This work was supported by the European Union (Marie-Curie International Reintegration grant no. 256502 to S.W.), the Deutsche Forschungsgemeinschaft Collaborative Research Centre (grant no. SFB1101 to S.W.), the European Research Council (grant no. 336295 to S.W.), and the Spanish MINECO (grant no. BIO2011–23489 to J.F.M.-G.).Peer reviewe

Estimulación precoz : aplicación a la ceguera congénita

Obtener a través de la estimulación temprana la mayor potenciación y desarrollo de los niños cuya evolución se halla en riesgo de no cumplirse normalmente, mediante el aporte de un ambiente estimulante físico-humano rico y estructurado. El desarrollo del niño depende tanto de la maduración como del aprendizaje. Es el medio quien posibilita o impide la expresión de las capacidades con las que el niño llega al mundo: es necesario que este les procure la posibilidad de manifestarse y ofrezca la forma en que estas disposiciones se desarrollen. El objetivo de los programas de estimulación precoz es la maxima potenciación y desarrollo de las capacidades del niño, mediante una estimulación regulada, continuada y acorde a sus posibilidades. Estos programas se dirigen esencialmente a aquellos niños cuyo desarrollo se ve afectado por factores, bien hereditarios, biológicos o ambientales, pero, por la filosofía que subyace a los mismos, abogan por una educación preescolar generalizada, que tendría un carácter profiláctico de posibles perturbaciones y facilitador de la vida escolar y personal de los niños. Dado su vasto campo de aplicación y probada la influencia decisiva de la intervención temprana en la evolución del niño se hace necesaria su implantanción progresiva, para lo que considero fundamental la toma de conciencia y el conocimiento colectivo del problema y la creación de centros de detección y diagnóstico precoz y de prestación de tratamientos dentro de una estructura coordinada y coherente.Castilla y LeónES

Early Signaling in plant immunity /

During pathogen infection, plants recognize microbial molecules known as pathogen associated molecular patterns (PAMPS) by surface localized pattern recognition receptors (PRRs), these results in physiological changes that limit pathogen growth in a process known as PAMP-triggered immunity (PTI). Recognition of PAMPs triggers the production of the phytohormone salicylic acid (SA), which is important for defense against biotrophic pathogens and requires redox regulated NONEXPRESSER OF PR GENES1 (NPR1), a master regulator of SA- mediated defense. Although there is significant research on the transcriptional changes related to defense signaling, there is limited information on the early defense related protein changes that occurs before major transcriptional changes. Here we present the mass spectrometry result of early changes in protein abundance, and phosphorylation of Arabidopsis thaliana plants treated with defense elicitor BTH. We observed that 48 proteins changed in abundance, and 43 in phosphorylation following BTH treatment. We also analyzed the changes in abundance in NPR1 mutant (npr1-1) and observed that 43 proteins changed in abundance. We characterized the roles of 9 of the observed proteins in defense against three pathogens Hyaloperonospora arabidopsidis (Hpa), Pseudomonas syringae pv. (Pto) DC3000, and Botrytis cinerea. Our results reveal the novel role of 2 proteins in defense against PtoDC3000, 5 proteins in defense against Hpa and 3 proteins in defense against botrytis. We further analyzed the BTH induced proteome changes observed in our mass spectrometry results of the total proteome, phosphoproteome and npr1-1 proteome with STRING, an online database of known and predicted protein interactions. The predicted networks created from STRING were used in combination with our infection bioassay results to predict the roles of our proteins in known and novel defense networks. Our study emphasizes the strength of mass spectrometry as a tool to discover proteins with observable phenotypes and to predict novel protein network

Control of flowering in rice through synthetic microProteins

Photoperiod-dependent flowering in rice is regulated by HEADING DATE 1 (Hd1), which acts as both an activator and repressor of flowering in a daylength-dependent manner. To investigate the use of microProteins as a tool to modify rice sensitivity to the photoperiod, we designed a synthetic Hd1 microProtein (Hd1miP) capable of interacting with Hd1 protein, and overexpressed it in rice. Transgenic OX-Hd1miP plants flowered significantly earlier than wild type plants when grown in non-inductive long day conditions. Our results show the potential of microProteins to serve as powerful tools for modulating crop traits and unraveling protein function

The microProteins miP1a/b act by engaging CO in a TOPLESS/TOPLESS-like co-repressor complex.

<p>(<b><i>A</i></b>) Representative image series of co-localization studies of GFP-CO and RFP-TPL co transformed with either miP1a (n = 15), the B-Box-dead version miP1a* (n = 16) or miP1aΔPFVFL (n = 9) that is lacking the TPL-interaction motif. (<b><i>B</i></b>) Yeast-three-hybrid demonstrating the formation of a CO-TPL-miP1a trimeric complex. Growth of serial dilutions on non-selective SD-medium lacking leucine, tryptophan and uracil (-L/-W/-U) show normal yeast growth. Only positive interactions were able to grow on restrictive growth medium supplemented with 10mM 3-Aminotriazole (3-AT) and lacking histidine. (<b><i>C</i></b>) <i>In vitro</i> pull-down experiments. Recombinant MBP-CO, GST-miP1a, GST-miP1aΔPFVFL, GST-ZPR3 and HIS-TPL proteins were produced in <i>E</i>. <i>coli</i>. After cell lysis, cell extracts of MBP-CO and HIS-TPL were mixed with GST-miP1a, GST-miP1aΔPFVFL or GST-ZPR3 and incubated with magnetic anti-GST coupled magnetic beads (Promega). GST-miP1a, GST-miP1aΔPFVFL and GST-ZPR3 complexes were precipitated and washed using a magnetic stand, eluted by boiling in SDS-loading buffer and separated by SDS-PAGE. HIS-TPL and MBP-CO Proteins were detected by immunoblotting. (<b><i>D</i></b>) <i>In vitro</i> pull-down experiment of the trimeric TPL-miP1a-CO complex. MBP-CO and HIS-TPL were mixed with either miP1a or miP1a* proteins. After immunoprecipitation of MBP-CO with an amylose resin proteins were detected by immunoblotting.</p