The ins and outs of meiosis

Dale, Brian; Marino, Marcella; Wilding, Martin

doi:10.1002/(sici)1097-010x(19991015)285:3<226::aid-jez5>3.0.co;2-z

Cited by 7 publications

(3 citation statements)

References 109 publications

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“…Rather, this is accomplished by the maturation-inducing steroids 17,20 β -dihydroxy-4-pregnen-3-one (DHP) and 17,20 β ,21-trihydroxy-4-pregnen-3-one (20 β -S), the latter synthesized from 11-deoxycortisol [50, 51]. CYP51 mRNA was expressed in sea urchin ovary, but there is no indication that sterols are involved in the release from meiotic arrest in echinoderms [52, 53]. The absence of a CYP51 gene in Ciona spp.…”

Section: Discussionmentioning

confidence: 99%

Identification, modeling and ligand affinity of early deuterostome CYP51s, and functional characterization of recombinant zebrafish sterol 14α-demethylase

Morrison

Goldstone

Lamb

et al. 2014

Biochimica et Biophysica Acta (BBA) - General Subjects

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Background Sterol 14α-demethylase (cytochrome P450 51, CYP51, P45014DM) is a microsomal enzyme that in eukaryotes catalyzes formation of sterols essential for cell membrane function and as precursors in biosynthesis of steroid hormones. Functional properties of CYP51s are unknown in non-mammalian deuterostomes. Methods PCR-cloning and sequencing and computational analyses (homology modeling and docking) addressed CYP51 in zebrafish Danio rerio, the reef fish sergeant major Abudefduf saxatilis, and the sea urchin Strongylocentrotus purpuratus. Following N-terminal amino acid modification, zebrafish CYP51 was expressed in Escherichia coli, and lanosterol 14α-demethylase activity and azole inhibition of CYP51 activity were characterized using GC/MS. Results Molecular phylogeny positioned S. purpuratus CYP51 at the base of the deuterostome clade. In zebrafish, CYP51 is expressed in all organs examined, most strongly in intestine. The recombinant protein bound lanosterol and catalyzed 14α-demethylase activity, at 3.2 nmol/min/nmol CYP51. The binding of azoles to zebrafish CYP51 gave KS (dissociation constant) values of 0.26 μM for ketoconazole and 0.64 μM for propiconazole. Displacement of carbon monoxide also indicated zebrafish CYP51 has greater affinity for ketoconazole. Docking to homology models showed that lanosterol docks in fish and sea urchin CYP51s with an orientation essentially the same as in mammalian CYP51. Docking of ketoconazole indicates it would inhibit fish and sea urchin CYP51s. Conclusions Biochemical and computational analyses are consistent with lanosterol being a substrate for early deuterostome CYP51s. General Significance The results expand the phylogenetic view of animal CYP51, with evolutionary, environmental and therapeutic implications.

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Section: Discussionmentioning

confidence: 99%

Identification, modeling and ligand affinity of early deuterostome CYP51s, and functional characterization of recombinant zebrafish sterol 14α-demethylase

Morrison

Goldstone

Lamb

et al. 2014

Biochimica et Biophysica Acta (BBA) - General Subjects

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“…In the IVF process, the sperm activates development of the fertilized egg by inducing a prolonged series of oscillations in cytosolic free Ca 2ϩ concentration (Roger et al, 2004). Oocytes can be activated after SCNT by exposure to electrical pulse and chemical agents, which act by stimulating calcium oscillations (Dale et al, 1999), and different activation rates and subsequent development may result from the different Ca 2ϩ concentration oscillations when various activation protocols were employed.…”

Section: Discussionmentioning

confidence: 99%

Human Embryos Derived by Somatic Cell Nuclear Transfer Using an Alternative Enucleation Approach

Liu

Wang

et al. 2009

Cloning and Stem Cells

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Somatic cell nuclear transfer (SCNT) was used to generate patient-specific embryonic stem cells (ESCs) from blastocysts cloned by nuclear transfer (ntESCs). In this study, a total of 135 oocytes were obtained from 12 healthy donors (30-35 years). Human oocytes, obtained within 2 h following transvaginal aspiration, were enucleated using a Spindle Imaging System to position the spindle and chromosomes that lay on the metaphase plate, and a Zona Infrared Laser Optical System was used to open a single hole in the zona pellucida at the ~ 2 o'clock position. Human fibroblasts and lymphocytes were used to construct SCNT embryos. Nearly half (26 of 58) of the oocytes were fused after electrofusion and embryo development rates were 96.2% (two-cell, 25 of 26), 92.3% (four-cell, 24 of 26), 61.5% (eight-cell, 16 of 26), 34.6% (16-cell, 9 of 26), 26.9% (morula, 7 of 26), and 19.2% (blastocyst, 5 of 26), respectively, following incubation in improved G-series sequential medium. One cloned blastocyst was used for STR-DNA identification and genetic polymorphism analysis of mtDNA, and STR-DNA analysis of all cloned blastocysts indicated they were derived from SCNT. Quantitative analysis showed that mtDNA of cloned embryos reflected the change tendency of those observed in human IVF embryos. Our research provides an alternative enucleation approach for producing human SCNT-derived blastocysts, and may aid in providing a new method for human therapeutic cloning.

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“…The arrest is necessary for oocyte growth, preventing parthenogenetic reproduction, and coordination between oocyte maturation and reproductive cycles. The arrest may occur in different ways and times in different species (Albertini and Carabatsos, 1998;Colas and Dube, 1998;Kishimoto, 1998;Russo et al, 1998;Sagata, 1998;Yamashita, 1998;Dale et al, 1999;Ferrell, 1999). In many species two arrest phases exist: prophase of the first meiosis in virtually all species, and metaphase of meiosis I or II.…”

Section: Introductionmentioning

confidence: 99%

Effects of MAP kinase pathway and other factors on meiosis ofUrechis unicinctus eggs

et al. 2005

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The eggs of Urechis unicinctus Von Drasche, an echiuroid, are arrested at P-I stage in meiosis. The meiosis is reinitiated by fertilization. Immunoblotting analysis using anti-ERK2 and anti-phospho-MAPK antibodies revealed a 44 kDa MAP kinase species that was constantly expressed in U. unicinctus eggs, quickly phosphorylated after fertilization, and dephosphorylated slowly before the completion of meiosis I. Phosphorylation of the protein was not depressed by protein synthesis inhibitor Cycloheximide (CHX), but was depressed by the MEK1 inhibitor PD98059. Under PD98059 treatment, polar body extrusion was suppressed and the function of centrosome and spindle was abnormal though GVBD was not affected, indicating that MAP kinase cascade was important for meiotic division of U. unicinctus eggs. Other discovery includes: A23187 and OA could parthenogenetically activate U. unicinctus eggs and phosphorylated 44 kDa MAP kinase species, indicating that the effect of fertilization on reinitiating meiosis and phosphorylation of 44 kDa MAP kinase specie is mediated by raising intracellular free calcium and by phosphorylation of some proteins, and that phosphotase(s) sensitive to OA is responsible for arresting U. unicinctus eggs in prophase I. diC8, an activator of PKC, accelerated the process of U. unicinctus egg meiotic division after fertilization and accelerated the dephosphorylation of 44 kDa MAP kinase specie, which implied that the acceleration effect of PKC on meiotic division was mediated by inactivation of MAP kinase cascade. Elevating cAMP/PKA level in U. unicinctus eggs had no effect on meiotic division of the eggs.

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The ins and outs of meiosis

Cited by 7 publications

References 109 publications

Identification, modeling and ligand affinity of early deuterostome CYP51s, and functional characterization of recombinant zebrafish sterol 14α-demethylase

Identification, modeling and ligand affinity of early deuterostome CYP51s, and functional characterization of recombinant zebrafish sterol 14α-demethylase

Human Embryos Derived by Somatic Cell Nuclear Transfer Using an Alternative Enucleation Approach

Effects of MAP kinase pathway and other factors on meiosis ofUrechis unicinctus eggs

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