排序方式: 共有53条查询结果,搜索用时 15 毫秒
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Daniel CB Jeffery Naoko Kakusho Zhiying You Marlene Gharib Brandon Wyse Erin Drury Michael Weinreich Pierre Thibault Alain Verreault Hisao Masai Krassimir Yankulov 《Cell cycle (Georgetown, Tex.)》2015,14(1):74-85
Chromatin Assembly Factor I (CAF-I) plays a key role in the replication-coupled assembly
of nucleosomes. It is expected that its function is linked to the regulation of the cell
cycle, but little detail is available. Current models suggest that CAF-I is recruited to
replication forks and to chromatin via an interaction between its Cac1p subunit and the
replication sliding clamp, PCNA, and that this interaction is stimulated by the kinase
CDC7. Here we show that another kinase, CDC28,
phosphorylates Cac1p on serines 94 and 515 in early S phase and regulates its association
with chromatin, but not its association with PCNA. Mutations in the Cac1p-phosphorylation
sites of CDC28 but not of CDC7 substantially reduce the
in vivo phosphorylation of Cac1p. However, mutations in the putative
CDC7 target sites on Cac1p reduce its stability. The association of
CAF-I with chromatin is impaired in a cdc28–1 mutant and to a
lesser extent in a cdc7–1 mutant. In addition, mutations in the
Cac1p-phosphorylation sites by both CDC28 and CDC7
reduce gene silencing at the telomeres. We propose that this phosphorylation represents a
regulatory step in the recruitment of CAF-I to chromatin in early S phase that is distinct
from the association of CAF-I with PCNA. Hence, we implicate CDC28 in the
regulation of chromatin reassembly during DNA replication. These findings provide novel
mechanistic insights on the links between cell-cycle regulation, DNA replication and
chromatin reassembly. 相似文献
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Two contrasting approaches have been used to construct the overall tree of life from molecular data: one involves the analysis of single large datasets, while the other involves joining many independent smaller analyses into a supertree. A recent study uses the latter approach to produce the most complete phylogeny yet of flowering plant families. 相似文献
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Untransformed bovine anterior pituitary cells cultured in serum-free defined medium secrete an epidermal growth factor (EGF)-like peptide with an amino acid composition similar to rat or human alpha-transforming growth factor (alpha TGF). To further characterize the bovine pituitary alpha TGF, it was compared to a human alpha TGF partially purified from the conditioned medium of a human melanoma cell line. An anti-alpha TGF monoclonal antibody, MF9, was produced from hybridomas derived from mice immunized with a 17-residue synthetic peptide corresponding to the carboxyl-terminal sequence of rat alpha TGF. The hybridoma supernatants were initially screened for the ability to immunoprecipitate 125I-peptide and then tested for recognition of human alpha TGF. Only 2 of 36 antipeptide antibodies recognized the native alpha TGF. The binding of 125I-peptide to MF9 was displaced by human alpha TGF but not by EGF. Bovine pituitary alpha TGF also displaced the binding of 125I-peptide to MF9 in a similar manner to human alpha TGF. Both iodinated human and bovine pituitary alpha TGF were immunoprecipitated by MF9 whereas 125I-EGF was not. Recognition of alpha TGF by MF9 was strongly dependent on sulfhydryl reduction of the growth factors, suggesting that synthetic peptides representing sulfhydryl-rich protein are not ideal immunogens. Tryptic digests of both 125I-alpha TGFs chromatographed to give a single, indistinguishable peak of iodinated material on a reverse-phase C18 high performance liquid chromatography column when eluted with two different solvent systems, suggesting the generation of a single and identical tyrosine-containing tryptic peptide from both alpha TGFs. The comparisons of the bovine pituitary and human melanoma alpha TGF using a sequence-specific monoclonal antibody and peptide mapping suggest that these alpha TGFs are related and that alpha TGF production is not limited to transformed or fetal sources. 相似文献
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A. N. Sinel'nikova E. G. Sologubov A. B. Yavorskii V. I. Kobrin S. A. Nemkova A. A. Beznosova 《Human physiology》2001,27(3):312-316
The CNS can precisely assess the spatial position of the human body only by simultaneously processing and integrating the visual, proprioceptive, and vestibular inputs. Postural stability data make it possible to estimate changes taking place in the function of analyzers involved in the maintenance of the upright posture. The vertical posture stability was assessed in healthy children and children with spastic diplegic cerebral palsy from their postural responses to the presentation of single optokinetic or somatosensory stimuli. The visual analyzer was found to play a significant role in maintaining the upright position under natural gravity conditions in healthy children. A single exposure of the proprioceptive system to variable forces directed with the gravity of the earth (vertical) decreased the contribution of the visual analyzer. Healthy children maintained the upright position relying on the direction of movement of the optokinetic stimuli, which, however, produced no effect on the maintenance of posture in the patients. A hypothesis is proposed that prenatal or early postnatal CNS lesions decrease the contribution of phylogenetically newer brain structures to the regulation of upright posture. 相似文献
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The lengthening of conceptive delays under conditions of natural fertility by cyclic spouse separation is investigated as a problem in renewal processes. Separations are “complete” if they reduce the conditional monthly probability of conception, or fecundability, to zero, and “incomplete” if they merely reduce it, from f to r say. Earlier work respecting cyclic separation by Menken (1979) is extended with formulas for the mean and variance of conceptive delays conditional on T, the ordinal month of the cycle of separation and nonseparation when the woman passes from anovulation into the fecundable state. A simple expression relating fecundabilities f and r and the conditional proportions Ps(T) and Ps-(T) conceiving during separation and nonseparation is obtained. 相似文献
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V I Kobrin 《Biulleten' eksperimental'no? biologii i meditsiny》1992,114(10):339-340
The parameters of transmembrane potentials of cardiomyocytes and dynamics of fibrillation process have been investigated when altering the level of sympathetic action on the heart by injection of rausedile, katecholamines and by stimulation of the nucleus of hypothalamus. It was shown that the injection of rausedile decreases rest potential and potential activity, meanwhile electrical irritation significantly increases the period of spontaneously reversible fibrillation. 相似文献
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Asha Tukappa NK Ramesh L Londonkar Hanumantappa B Nayaka Sanjeev Kumar CB 《Biological research》2015,48(1)