A collection of enhancer trap insertional mutants for functional genomics in tomato

[EN] With the completion of genome sequencing projects, the next challenge is to close the gap between gene annotation and gene functional assignment. Genomic tools to identify gene functions are based on the analysis of phenotypic variations between a wild type and its mutant; hence, mutant collections are a valuable resource. In this sense, T-DNA collections allow for an easy and straightforward identification of the tagged gene, serving as the basis of both forward and reverse genetic strategies. This study reports on the phenotypic and molecular characterization of an enhancer trap T-DNA collection in tomato (Solanum lycopersicum L.), which has been produced by Agrobacterium-mediated transformation using a binary vector bearing a minimal promoter fused to the uidA reporter gene. Two genes have been isolated from different T-DNA mutants, one of these genes codes for a UTP-glucose-1-phosphate uridylyltransferase involved in programmed cell death and leaf development, which means a novel gene function reported in tomato. Together, our results support that enhancer trapping is a powerful tool to identify novel genes and regulatory elements in tomato and that this T-DNA mutant collection represents a highly valuable resource for functional analyses in this fleshy-fruited model species.This work was supported by research grants from the Spanish Ministerio de Economia y Competitividad (AGL2012-40150-C02-01, AGL2012-40150-C02-02, AGL2015-64991-C3-1-R and AGL2015-64991-C3-3-R), Junta de Andalucia (P10-AGR-6931) and UE-FEDER. B.P. received a JAE-Doc research contract from the CSIC (Spain). PhD fellowships were funded by the FPU (M.G-A. and R.F.) and the FPI (M.P.A., S.S.A. F-L., A.O-A and L.C.) Programmes of the Ministerio de Ciencia e Innovacion, the JAE predoc Programme of the Spanish CSIC (G.G.), the CONACYT and Universidad de Sinaloa of Mexico (J.S.) and the LASPAU (J.L.Q.). The authors thank research facilities provided by the Campus de Excelencia Internacional Agroalimentario (CeiA3)Pérez-Martín, F.; Yuste-Lisbona, FJ.; Pineda Chaza, BJ.; Angarita-Díaz, MP.; García Sogo, B.; Antón Martínez, MT.; Sanchez Martín-Sauceda, S.... (2017). A collection of enhancer trap insertional mutants for functional genomics in tomato. Plant Biotechnology Journal. 15(11):1439-1452. https://doi.org/10.1111/pbi.12728S14391452151

Chancengleiche Palliative Care: Bedarf und Bedürfnisse der Migrationsbevölkerung in der Schweiz

Auf dem Weg vom Nischenangebot zur breit zugänglichen Dienstleistung interessieren in der Palliative Care vermehrt auch Fragen der Chancengleichheit. In der Schweiz wird mit der «Nationalen Strategie Palliative Care» darauf hin gearbeitet, dass schwerkranke und sterbende Menschen eine ihren Bedürfnissen angepasste Palliative Care erhalten und ihre Lebensqualität verbessert wird. Es ist jedoch weder bekannt, welche Kenntnisse die Migrationsbevölkerung in der Schweiz über Palliative Care und über die Angebote hat, noch ob sie diese Angebote ausreichend in Anspruch nimmt

CACNA1I gain-of-function mutations differentially affect channel gating and cause neurodevelopmental disorders

T-type calcium channels (Cav3.1 to Cav3.3) regulate low-threshold calcium spikes, burst firing and rhythmic oscillations of neurons and are involved in sensory processing, sleep, and hormone and neurotransmitter release. Here, we examined four heterozygous missense variants in CACNA1I, encoding the Cav3.3 channel, in patients with variable neurodevelopmental phenotypes. The p.(Ile860Met) variant, affecting a residue in the putative channel gate at the cytoplasmic end of the IIS6 segment, was identified in three family members with variable cognitive impairment. The de novo p.(Ile860Asn) variant, changing the same amino acid residue, was detected in a patient with severe developmental delay and seizures. In two additional individuals with global developmental delay, hypotonia, and epilepsy, the variants p.(Ile1306Thr) and p.(Met1425Ile), substituting residues at the cytoplasmic ends of IIIS5 and IIIS6, respectively, were found. Because structure modelling indicated that the amino acid substitutions differentially affect the mobility of the channel gate, we analysed possible effects on Cav3.3 channel function using patch-clamp analysis in HEK293T cells. The mutations resulted in slowed kinetics of current activation, inactivation, and deactivation, and in hyperpolarizing shifts of the voltage-dependence of activation and inactivation, with Cav3.3-I860N showing the strongest and Cav3.3-I860M the weakest effect. Structure modelling suggests that by introducing stabilizing hydrogen bonds the mutations slow the kinetics of the channel gate and cause the gain-of-function effect in Cav3.3 channels. The gating defects left-shifted and increased the window currents, resulting in increased calcium influx during repetitive action potentials and even at resting membrane potentials. Thus, calcium toxicity in neurons expressing the Cav3.3 variants is one likely cause of the neurodevelopmental phenotype. Computer modelling of thalamic reticular nuclei neurons indicated that the altered gating properties of the Cav3.3 disease variants lower the threshold and increase the duration and frequency of action potential firing. Expressing the Cav3.3-I860N/M mutants in mouse chromaffin cells shifted the mode of firing from low-threshold spikes and rebound burst firing with wild-type Cav3.3 to slow oscillations with Cav3.3-I860N and an intermediate firing mode with Cav3.3-I860M, respectively. Such neuronal hyper-excitability could explain seizures in the patient with the p.(Ile860Asn) mutation. Thus, our study implicates CACNA1I gain-of-function mutations in neurodevelopmental disorders, with a phenotypic spectrum ranging from borderline intellectual functioning to a severe neurodevelopmental disorder with epilepsy

Developmental Disaster 1: A Novel Mutation Causing Defects During Vegetative And Inflorescence Development In Maize (Zea Mays, Poaceae)

Axillary meristems, which give rise to branches and flowers, play a critical role in plant architecture and reproduction. To understand how axillary meristems initiate, we have screened for mutants with defects in axillary meristem initiation to uncover the genes controlling this process. These mutants, called the barren class of mutants in maize (Zea mays), have defects in axillary meristem initiation during both vegetative and reproductive development. Here, we identify and characterize a new member of the barren class of mutants named Developmental disaster1 (Dvd1), due to the pleiotropic effects of the mutation. Similar to the barren mutants, Dvd1 mutants have fewer branches, spikelets, florets, and floral organs in the inflorescence due to defects in the initiation of axillary meristems. Furthermore, double mutant analysis with teosinte branched1 shows that dvd1 also functions in axillary meristems during vegetative development. However, unlike the barren mutants, Dvd1 mutants are semidwarf due to the production of shorter internodes, and they produce leaves in the inflorescence due to the outgrowth of bract leaf primordia. The suite of defects seen in Dvd1 mutants, together with the genetic interaction of Dvd1 with barren inflorescence2, suggests that dvd1 is a novel regulator of axillary meristem and internode development