A family of genes required for maintenance of cell wall integrity and for the stress response in Saccharomyces cerevisiae

The PKC1–MPK1 pathway in yeast functions in the maintenance of cell wall integrity and in the stress response. We have identified a family of genes that are putative regulators of this pathway. WSC1, WSC2, and WSC3 encode predicted integral membrane proteins with a conserved cysteine motif and a WSC1–green fluorescence protein fusion protein localizes to the plasma membrane. Deletion of WSC results in phenotypes similar to mutants in the PKC1–MPK1 pathway and an increase in the activity of MPK1 upon a mild heat treatment is impaired in a wscΔ mutant. Genetic analysis places the function of WSC upstream of PKC1, suggesting that they play a role in its activation. We also find a genetic interaction between WSC and the RAS–cAMP pathway. The RAS–cAMP pathway is required for cell cycle progression and for the heat shock response. Overexpression of WSC suppresses the heat shock sensitivity of a strain in which RAS is hyperactivated and the heat shock sensitivity of a wscΔ strain is rescued by deletion of RAS2. The functional characteristics and cellular localization of WSC suggest that they may mediate intracellular responses to environmental stress in yeast.

The length of telomeric G-rich strand 3′-overhang measured by oligonucleotide ligation assay

A typical G-rich telomeric DNA strand, which runs 5′→3′ toward the chromosome ends, protrudes by several nucleotides in lower eukaryotes. In human chromosomes long G-rich 3′-overhangs have been found. Apart from the standard G-rich tail, several non-canonical terminal structures have been proposed. However, the mechanism of long-tail formation, the presence and the role of these structures in telomere maintenance or shortening are not completely understood. In a search for a simple method to accurately measure the 3′-overhang we have established a protocol based on the ligation of telomeric oligonucleotide hybridized to non-denatured DNA under stringent conditions (oligonucleotide ligation assay with telomeric repeat oligonucleotide). This method enabled us to detect a large proportion of G-rich single-stranded telomeric DNA that was as short as 24 nt. Nevertheless, we showed G-tails longer than 400 nt. In all tested cells the lengths ranging from 108 to 270 nt represented only 37% of the whole molecule population, while 56–62% were <90 nt. Our protocol provides a simple and sensitive method for measuring the length of naturally occurring unpaired repeated DNA.

Co-evaluación y autoevaluación a través de Moodle-UA para asignaturas de lenguas y literaturas extranjeras

La implementación de la evaluación formativa en asignaturas del Departamento de Filologías Integradas desde hace ya cinco años, cuando iniciamos nuestra investigación en este campo, nos ha llevado a plantearnos la utilización de nuevos instrumentos y herramientas de evaluación. La plataforma virtual Moodle-UA 2 disponía de utilidades a las que podían adaptarse perfectamente las asignaturas de lenguas y literaturas extranjeras que impartimos desde del departamento de Filologías Integradas. Nuestro principal propósito ha sido el de formarnos en la utilización y conocimiento de las posibilidades que esta plataforma virtual ofrecía en materia de evaluación. Nos hemos centrado sobre todo en la adaptación de los cuestionarios de autoevaluación y coevaluación vinculados a las actividades formativas evaluables de nuestras asignaturas, a las herramientas de la plataforma. En este sentido, hemos trabajado en la manera de vincular todos los aspectos de la evaluación formativa a través de la plataforma Moodle- UA para así optimizar y agilizar el proceso, tanto para el docente como para el discente.