The Mos protein kinase is a key regulator of vertebrate oocyte maturation. Oocyte-specific Mos protein expression is subject to translational control. In the frog Xenopus, the translation of Mos protein requires the progesterone-induced polyadenylation of the maternal Mos mRNA, which is present in the oocyte cytoplasm. Both the Xenopus p42 mitogen-activated protein kinase (MAPK) and maturation-...

Commitment to mitosis is regulated by a conserved protein kinase complex called MPF (mitosis-promoting factor). MPF activation triggers a positive-feedback loop that further promotes the activity of its activating phosphatase Cdc25 and is assumed to down-regulate the MPF-inhibitory kinase Wee1. Four protein kinases contribute to this amplification loop: MPF itself, Polo kinase, MAPK (mitogen-ac...

Recently, the marginalized particle filter (MPF) has been applied to blind symbol detection problems over selective fading channels. The MPF can ease the computational burden of the standard particle filter (PF) while offering better estimates compared with the standard PF. In this paper, we investigate the application of the blind MPF detector to more realistic situations where the systems suf...

In full-grown Xenopus oocytes, cell-cycle regulators and an inactive form of maturation/M phase promoting factor (pre-MPF) are stored ready to bring about a specific cell cycle for oocyte maturation. We examined the expression pattern of these cell-cycle regulators as well as pre-MPF formation during oogenesis. Cdc2 and Cyclin B2 were already present in stage I oocytes and pre-MPF formation was...

Pumpkin waste powder was used as a coloring and strengthening filler in epoxy to prepare natural gelcoat . The mixed with different weight ratios (1, 2, 3, 4, 5, 6, 7, 8%) the matrix select best value of addition. effect pumpkin particle size on mechanical properties (impact, flexural, hardness, wear loss) using two sizes (2.5 1.25 microns) studied. impact strength increased from (10.09 KJ/ m2)...

Progression through meiosis requires two waves of maturation promoting factor (MPF) activity corresponding to meiosis I and meiosis II. Frog oocytes contain a pool of inactive "pre-MPF" consisting of cyclin-dependent kinase 1 bound to B-type cyclins, of which we now find three previously unsuspected members, cyclins B3, B4 and B5. Protein synthesis is required to activate pre-MPF, and we show h...

BACKGROUND Tumor mesothelin overexpression is present in different malignancies, including the majority of patients with pancreatic or biliary cancers. The objective of this study was to evaluate the use of shed serum mesothelin and megakaryocyte potentiating factor (MPF) concentrations as biomarkers for these cancers. METHODS A total of 151 individuals, divided into five groups, were retrosp...

The interplay between maturation-promoting factor (MPF), mitogen-activated protein kinase (MAPK) and Rho GTPase during actin-myosin interactions has yet to be determined. The mechanism by which microtubule disrupters induce the formation of ooplasmic protrusion during chemical-assisted enucleation of mammalian oocytes is unknown. Moreover, a suitable model is urgently needed for the study of cy...

We have studied the effect of maturation-promoting factor (MPF) on embryonic nuclei during the early cleavage stage of Xenopus laevis development. When protein synthesis is inhibited by cycloheximide during this stage, the embryonic cell cycle arrests in an artificially produced G2 phase-like state, after completion of one additional round of DNA synthesis. Approximately 100 nuclei can be arres...

In eukaryotic cells, the key regulators of cell-cycle transitions are the cyclin-dependent kinases (CDKs). The best studied CDK is a component of the M-phase promoting factor (MPF), which promotes entry into and progression through meiosis and mitosis. One of the enduring mysteries of the MPF complex has been the role of Cks/Suc1, a highly conserved member of the cell-cycle machinery in eukaryo...