The regulation of mitotic entry in somatic cells differs from embryonic cells, yet it is only for embryonic cells that we have a quantitative understanding of this process. To gain a similar insight into somatic cells, we developed a human cell extract system that recapitulates CDK1 activation and nuclear envelope breakdown in response to mitotic cyclins. As cyclin B concentrations increase, CDK1 activates in a three-stage nonlinear response, creating an ordering of substrate phosphorylations. This response is established by dual regulatory feedback loops involving WEE1/MYT1, which impose a cyclin B threshold, and CDC25, which allows CDK1 to escape the WEE1/MYT1 inhibition. This system also exhibits a complex response to cyclin A. Cyclin A promotes WEE1 phosphorylation to weaken the negative feedback loop and primes mitotic entry through cyclin B. This observation explains the requirement of both cyclin A and cyclin B to initiate mitosis in somatic cells.
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http://dx.doi.org/10.1016/j.molcel.2010.02.023 | DOI Listing |
Front Cell Dev Biol
January 2025
Department of Health Promotion Sciences, Graduated School of Human Health Sciences, Tokyo Metropolitan University, Hachioji, Japan.
Cell therapy of skeletal muscles is a promising approach for the prevention of muscular diseases and age-related muscle atrophy. However, cell transplantation to treat muscle atrophy that does not involve disease, such as sarcopenia, is considered impossible because externally injected cells rarely engraft into non-injured muscle tissue. Additionally, skeletal muscle-specific somatic stem cells, called satellite cells, lose their ability to adhere to tissue after being cultured and transforming into myoblasts.
View Article and Find Full Text PDFActa Naturae
January 2024
Pluripotency Dynamics Group, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064 Russian Federation.
Embryonic stem cells (ESCs) hold great promise for regenerative medicine thanks to their ability to self-renew and differentiate into somatic cells and the germline. ESCs correspond to pluripotent epiblast - the tissue from which the following three germ layers originate during embryonic gastrulation: the ectoderm, mesoderm, and endoderm. Importantly, ESCs can be induced to differentiate toward various cell types by varying culture conditions, which can be exploited for modeling of developmental processes such as gastrulation.
View Article and Find Full Text PDFEur J Haematol
January 2025
Hematology, St. Paul's Hospital and The University of British Columbia, Vancouver, British Columbia, Canada.
Introduction: Iron overload (IOL) accumulates in myelodysplastic syndromes (MDS) from expanded erythropoiesis and transfusions. Somatic mutations (SM) are frequent in MDS and stratify patient risk. MDS treatments reversing or limiting transfusion dependence are limited.
View Article and Find Full Text PDFTrop Anim Health Prod
January 2025
Department of Clinical Sciences, Swedish University of Agricultural Sciences, Box 7024, 750 07, Uppsala, Sweden.
A cross-sectional study on 156 smallholder dairy farms in Rwanda was carried out to assess the association between farm management practices and milk yield and quality. A pre-tested questionnaire was used to collect data on cow characteristics and farm management practices. Milk yield was recorded at household level, milk composition was monitored using a Lactoscan device (Milk Analyzer).
View Article and Find Full Text PDFNat Commun
January 2025
State Key Laboratory of Primate Biomedical Research; Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, Yunnan, China.
Blastoids-blastocyst-like structures created in vitro-emerge as a valuable model for early embryonic development research. Non-human primates stem cell-derived blastoids are an ethically viable alternative to human counterparts, yet the low formation efficiency of monkey blastoid cavities, typically below 30%, has limited their utility. Prior research has predominantly utilized embryonic stem cells.
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