Alfvén pulse driven spicule-like jets in the presence of thermal conduction and ion-neutral collision in two-fluid regime.

We present the formation of quasi-periodic cool spicule-like jets in the solar atmosphere using 2.5-D numerical simulation in two-fluid regime (ions+neutrals) under the presence of thermal conduction and ion-neutral collision. The nonlinear, impulsive Alfvénic perturbations at the top of the photosphere trigger field aligned magnetoacoustic perturbations due to ponderomotive force.

Histone H3 serine-57 is a CHK1 substrate whose phosphorylation affects DNA repair.

Histone post-translational modifications promote a chromatin environment that controls transcription, DNA replication and repair, but surprisingly few phosphorylations have been documented. We report the discovery of histone H3 serine-57 phosphorylation (H3S57ph) and show that it is implicated in different DNA repair pathways from fungi to vertebrates. We identified CHK1 as a major human H3S57 kinase, and disrupting or constitutively mimicking H3S57ph had opposing effects on rate of recovery from replication stress, 53BP1 chromatin binding, and dependency on RAD52.

Role of Cdc23/Mcm10 in generating the ribonucleotide imprint at the mat1 locus in fission yeast.

The developmental asymmetry of fission yeast daughter cells derives from inheriting 'older Watson' versus 'older Crick' DNA strand from the parental cell, strands that are complementary but not identical with each other. A novel DNA strand-specific 'imprint', installed during DNA replication at the mating-type locus (mat1), imparts competence for cell type inter-conversion to one of the two chromosome replicas. The catalytic subunit of DNA Polymerase α (Polα) has been implicated in the imprinting process.

Linking the organization of DNA replication with genome maintenance.

The spatial and temporal organization of genome duplication, also referred to as the replication program, is defined by the distribution and the activities of the sites of replication initiation across the genome. Alterations to the replication profile are associated with cell fate changes during development and in pathologies, but the importance of undergoing S phase with distinct and specific programs remains largely unexplored. We have recently addressed this question, focusing on the interplay between the replication program and genome maintenance.

Regulation of the program of DNA replication by CDK: new findings and perspectives.

Progression through the cell cycle is driven by the activities of the cyclin-dependent kinase (CDK) family of enzymes, which establish an ordered passage through the cell cycle phases. CDK activity is crucial for the cellular transitions from G1 to S and G2 to M, which are highly controlled to promote the faithful duplication of the genetic material and the transmission of the genome into daughter cells, respectively. While oscillations in CDK activity are essential for cell division, how its specific dynamics may shape cellular processes remains an open question.

A fast and inexpensive method for random spore analysis in Schizosaccharomyces pombe.

Random spore analysis is a fundamental tool of yeast genetics for determining gene linkage and the generation of recombinant progeny by genetic crosses. Experimentally it involves treatment of a mating mix with enzymes, such as zymolyase or lyticase, that selectively lyse the cell wall of vegetative cells rather than the spores. Here, we describe a method whereby the relative refractory nature of the spores to treatment with elevated temperature and repeated freeze-thawing facilitates random spore analysis at low cost in fission yeast Schizosaccharomyces pombe.