In vertebrates, oocytes undergo maturation, arrest in metaphase II, and can then be fertilized by sperm. Fertilization initiates molecular events that lead to the activation of early embryonic development. In Caenorhabditis elegans, where no delay between oocyte maturation and fertilization is apparent, oocyte maturation and fertilization must be tightly coordinated. It is not clear what coordi...

Cdc25 is an evolutionarily conserved protein phosphatase that promotes progression through the cell cycle. Some metazoans have multiple isoforms of Cdc25, which have distinct functions and different expression patterns during development. C. elegans has four cdc-25 genes. cdc-25.1 is required for germline mitotic proliferation. To determine if the other members of the cdc-25 family also contrib...

The kinase Mos, which activates intracellularly the MAP kinase pathway, is a key regulator of animal oocyte meiotic maturation. In vertebrate and echinoderm models, Mos RNA translation upon oocyte hormonal stimulation mediates "cytostatic" arrest of the egg after meiosis, as well as diverse earlier events [1-5]. Our phylogenetic survey has revealed that MOS genes are conserved in cnidarians and...

The seed represents the unit of reproduction of flowering plants, capable of developing into another plant, and to ensure the survival of the species under unfavorable environmental conditions. It is composed of three compartments: seed coat, endosperm and embryo. Proper seed development depends on the coordination of the processes that lead to seed compartments differentiation, development and...

The protein encoded by the IRR1/SCC3 gene is an element of the cohesin complex of Saccharomyces cerevisiae, responsible for establishing and maintaining sister chromatid cohesion during mitotic cell division. We noticed previously that lowering the level of expression of IRR1/SCC3 affects colony formation on solid support. Here we describe two dosage suppressors (IST2, NOG2) overcoming the inab...

Eukaryotic replication disrupts each nucleosome as the fork passes, followed by re-assembly of disrupted nucleosomes and incorporation of newly synthesized histones into nucleosomes in the daughter genomes. In this review, we examine this process of replication-coupled nucleosome assembly to understand how characteristic steady state nucleosome landscapes are attained. Recent studies have begun...

There are three zones within the onion root tip, the meristematic zone, the zone of elongation, and the zone of maturation, all of which represent a different zone of the cells' lives, with cell division occurring actively in the meristematic zone. When a cell is ready to divide, its DNA becomes visible due to higher order structuring that starts with DNA binding to histones. Through tetrazoliu...

conclusion the relationship between calcification of teeth and maturation of cervical bones was significant. bone maturation can be predicted by using teeth calcification stages, especially in the second molar, first molar and lateral incisor. results correlations between the two stages were observed in the first and second premolars, canine and central incisors. all these correlations were sig...