ATR controls chromosome integrity and chromatin dynamics. We have previously shown that yeast Mec1/ATR promotes chromatin detachment from the nuclear envelope to counteract aberrant topological transitions during DNA replication. Here, we provide evidence that ATR activity at the nuclear envelope responds to mechanical stress. Human ATR associates with the nuclear envelope during S phase and pr...

The mechanism of nuclear envelope breakdown (NEBD) was investigated in live cells. Early spindle microtubules caused folds and invaginations in the NE up to one hour prior to NEBD, creating mechanical tension in the nuclear lamina. The first gap in the NE appeared before lamin B depolymerization, at the site of maximal tension, by a tearing mechanism. Gap formation relaxed this tension and dram...

Phosphorylation of histone H3 at serine 10 occurs during mitosis in diverse eukaryotes and correlates closely with mitotic and meiotic chromosome condensation. To better understand the function of H3 phosphorylation in vivo, we created strains of Tetrahymena in which a mutant H3 gene (S10A) was the only gene encoding the major H3 protein. Although both micronuclei and macronuclei contain H3 in ...

Interphase HeLa cells exposed to solutions that are 1.6 x isotonic manifest a series of morphological transformations, several of which grossly resemble those which occur when untreated cells enter prophase. These include chromosome condensation with preferential localization at the nuclear envelope and nucleolus, ruffling of the nuclear envelope, and polyribosome breakdown. The nucleolus loses...

The accumulation of gluons inside nucleons, i.e., the gluon condensation, may lead to a characteristic broken power-law gamma-ray spectrum in high-energy nucleon collisions. Here we show that observed spectra at least 25 sources second Fermi Large Area Telescope Catalog Gamma-ray Pulsars can be well fitted by such function has only four free parameters. It strongly indicates emission from these...

Changes in nuclear size, shape, and chromatin texture during spermiogenesis and epididymal transport of human sperm were recently analyzed using transmission electron microscopy (TEM) image cytometry followed by multivariate statistical analysis of data. In the present study, this same methodology was used to investigate the nuclear morphology of spermatozoa in semen samples from fertile and in...

Most plant species rely on seeds for their dispersal and survival under unfavorable environmental conditions. Seeds are characterized by their low moisture content and significantly reduced metabolic activities. During the maturation phase, seeds accumulate storage reserves and become desiccation-tolerant and dormant. Growth is resumed after release of dormancy and the occurrence of favorable e...

Male infertility affects approximately 50% of all infertile couples. The male-related causes of intracytoplasmic sperm injection failure include the absence of sperm, immotile or immature sperm, and sperm with structural defects such as those caused by premature chromosomal condensation and DNA damage. Our previous studies based on a knockout mice model indicated that SEPT12 proteins are critic...

Condensin is a protein complex associated with mitotic chromosomes that has been implicated in chromosome condensation. In vertebrates, two types of condensin complexes have recently been identified, called condensin I and II. Here, we show that in mammalian cells condensin II associates with chromatin in prophase, in contrast to condensin I which is cytoplasmic and can thus interact with chrom...

The linear sequence of DNA encodes access to the complete set of proteins that carry out cellular functions. Yet, much of the functionality appropriate for each cell is nested within layers of dynamic regulation and organization, including a hierarchy of chromatin structural states and spatial arrangement within the nucleus. There remain limitations in our understanding of gene expression withi...