Entry Name Oocyte meiosis - Xenopus laevis (African clawed frog)
Description During meiosis, a single round of DNA replication is followed by two rounds of chromosome segregation, called meiosis I and meiosis II. At meiosis I, homologous chromosomes recombine and then segregate to opposite poles, while the sister chromatids segregate from each other at meoisis II. In vertebrates, immature oocytes are arrested at the PI (prophase of meiosis I). The resumption of meiosis is stimulated by progesterone, which carries the oocyte through two consecutive M-phases (MI and MII) to a second arrest at MII. The key activity driving meiotic progression is the MPF (maturation-promoting factor), a heterodimer of CDC2 (cell division cycle 2 kinase) and cyclin B. In PI-arrested oocytes, MPF is initially inactive and is activated by the dual-specificity CDC25C phosphatase as the result of new synthesis of Mos induced by progesterone. MPF activation mediates the transition from the PI arrest to MI. The subsequent decrease in MPF levels, required to exit from MI into interkinesis, is induced by a negative feedback loop, where CDC2 brings about the activation of the APC (anaphase-promoting complex), which mediates destruction of cyclin B. Re-activation of MPF for MII requires re-accumulation of high levels of cyclin B as well as the inactivation of the APC by newly synthesized Emi2 and other components of the CSF (cytostatic factor), such as cyclin E or high levels of Mos. CSF antagonizes the ubiquitin ligase activity of the APC, preventing cyclin B destruction and meiotic exit until fertilization occurs. Fertilization triggers a transient increase in cytosolic free Ca2+, which leads to CSF inactivation and cyclin B destruction through the APC. Then eggs are released from MII into the first embryonic cell cycle.
Class Cellular Processes; Cell growth and deathBRITE hierarchy
Pathway map Other DBs Organism Xenopus laevis (African clawed frog) [GN:
xla ]
Gene 100037155 anapc13.2.L; anaphase promoting complex subunit 13, gene 2 L homeolog [KO:K12456 ]
100137650 zfp36l2.2.L; zinc finger protein 36, C3H type-like 2, gene 2 L homeolog [KO:K13056 ]
100137719 ppp2r5a.S; protein phosphatase 2 regulatory subunit B', alpha [KO:K11584 ]
100381102 ppp3cc.L; serine/threonine-protein phosphatase 2B catalytic subunit beta isoform isoform X1 [KO:K04348 ] [EC:3.1.3.16 ]
100505450 cpeb4.S; cytoplasmic polyadenylation element binding protein 4 S homeolog [KO:K02602 ]
108696257 camk2g.L; calcium/calmodulin-dependent protein kinase type II subunit gamma isoform X1 [KO:K04515 ] [EC:2.7.11.17 ]
108697486 anapc16.S; anaphase-promoting complex subunit 16-like [KO:K25229 ]
108698127 cdc26.L; anaphase-promoting complex subunit CDC26 isoform X1 [KO:K03359 ]
108699778 ppp2r5c.S; serine/threonine-protein phosphatase 2A 56 kDa regulatory subunit gamma isoform isoform X1 [KO:K11584 ]
108699983 smc1a.S; structural maintenance of chromosomes protein 1A-like [KO:K06636 ]
108701724 pkmyt1.L; membrane-associated tyrosine- and threonine-specific cdc2-inhibitory kinase-like isoform X1 [KO:K06633 ] [EC:2.7.11.1 ]
108705261 ppp3cc.S; serine/threonine-protein phosphatase 2B catalytic subunit beta isoform isoform X2 [KO:K04348 ] [EC:3.1.3.16 ]
108710719 smc1b.L; structural maintenance of chromosomes protein 1B [KO:K06636 ]
108712618 ppp2ca.S; serine/threonine-protein phosphatase 2A catalytic subunit alpha isoform [KO:K04382 ] [EC:3.1.3.16 ]
108712619 skp1.S; S-phase kinase-associated protein 1 isoform X2 [KO:K03094 ]
108717771 anapc1.S; anaphase-promoting complex subunit 1 isoform X1 [KO:K03348 ]
379130 cdc20.S; cell division cycle 20 S homeolog [KO:K03363 ]
379580 cdc23.L; cell division cycle 23 L homeolog [KO:K03355 ]
379626 pkmyt1.S; membrane-associated tyrosine- and threonine-specific cdc2-inhibitory kinase [KO:K06633 ] [EC:2.7.11.1 ]
379827 ppp2r1a.L; protein phosphatase 2 regulatory subunit A, alpha L homeolog [KO:K03456 ]
379914 ppp1ca.L; protein phosphatase 1, catalytic subunit, alpha isozyme L homeolog [KO:K06269 ] [EC:3.1.3.16 ]
379991 map2k1.L; dual specificity mitogen-activated protein kinase kinase 1 [KO:K04368 ] [EC:2.7.12.2 ]
380045 ppp2cal.S; protein phosphatase 2 catalytic subunit alpha-like S homeolog [KO:K04382 ] [EC:3.1.3.16 ]
380064 ywhaq.S; tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein theta S homeolog [KO:K16197 ]
380068 cdc23.S; cell division cycle 23 S homeolog [KO:K03355 ]
380100 ppp2r1b.S; protein phosphatase 2 regulatory subunit A, beta S homeolog [KO:K03456 ]
380182 smc1a.L; structural maintenance of chromosomes 1A L homeolog [KO:K06636 ]
380388 prkacb.S; protein kinase cAMP-activated catalytic subunit beta S homeolog [KO:K04345 ] [EC:2.7.11.11 ]
380397 ywhae.S; tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein epsilon S homeolog [KO:K06630 ]
380433 mad2l1.S; mitotic arrest deficient 2 like 1 S homeolog [KO:K02537 ]
380508 camk2g.S; calcium/calmodulin dependent protein kinase (CaM kinase) II gamma S homeolog [KO:K04515 ] [EC:2.7.11.17 ]
380538 skp1.L; S-phase kinase-associated protein 1 [KO:K03094 ]
380598 ppp1cc.S; serine/threonine-protein phosphatase PP1-gamma catalytic subunit B [KO:K06269 ] [EC:3.1.3.16 ]
394307 mad1l1.L; mitotic arrest deficient 1 like 1 L homeolog [KO:K06679 ]
394339 ppp2r1a.S; protein phosphatase 2 regulatory subunit A, alpha S homeolog [KO:K03456 ]
394380 mad2l2.S; mitotic spindle assembly checkpoint protein MAD2B [KO:K13728 ]
397767 ppp1cc.L; serine/threonine-protein phosphatase PP1-gamma catalytic subunit A [KO:K06269 ] [EC:3.1.3.16 ]
397789 camk2b.L; calcium/calmodulin dependent protein kinase (CaM kinase) II beta L homeolog [KO:K04515 ] [EC:2.7.11.17 ]
398044 cdc20.L; cell division cycle 20 L homeolog [KO:K03363 ]
398104 zfp36l2.1.S; zinc finger protein 36, C3H type-like 2, gene 1 S homeolog [KO:K13056 ]
398376 camk2d.L; calcium/calmodulin-dependent protein kinase type II delta chain-like isoform X8 [KO:K04515 ] [EC:2.7.11.17 ]
398888 ccnb2.L; uncharacterized protein LOC398888 [KO:K21770 ]
399092 smc3.L; structural maintenance of chromosomes 3 L homeolog [KO:K06669 ]
399160 camk2d.S; calcium/calmodulin-dependent protein kinase type II delta chain [KO:K04515 ] [EC:2.7.11.17 ]
399166 ppp2r5e.L; protein phosphatase-2A B'epsilon subunit [KO:K11584 ]
399254 itpr1.S; inositol 1,4,5-trisphosphate receptor type 1 S homeolog [KO:K04958 ]
399289 cpeb1.L; cytoplasmic polyadenylation element-binding protein 1-A [KO:K02602 ]
399343 ppp2cb.L; protein phosphatase 2, catalytic subunit, beta isozyme L homeolog [KO:K04382 ] [EC:3.1.3.16 ]
414530 anapc4.L; anaphase promoting complex subunit 4 L homeolog [KO:K03351 ]
414724 mad2l1.L; uncharacterized protein LOC414724 [KO:K02537 ]
432025 anapc15.S; anaphase-promoting complex subunit 15A [KO:K25228 ]
432106 ppp3cb.L; protein phosphatase 3, catalytic subunit, beta isozyme L homeolog [KO:K04348 ] [EC:3.1.3.16 ]
432330 smc3.S; structural maintenance of chromosomes 3 S homeolog [KO:K06669 ]
443852 ppp1cb.L; serine/threonine-protein phosphatase PP1-beta catalytic subunit [KO:K06269 ] [EC:3.1.3.16 ]
443949 anapc16.L; anaphase-promoting complex subunit 16 [KO:K25229 ]
443994 cdc27.S; cell division cycle protein 27 homolog [KO:K03350 ]
444832 ywhah.L; tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein eta L homeolog [KO:K16198 ]
446335 ppp2r5b.L; protein phosphatase 2 regulatory subunit B', beta [KO:K11584 ]
446574 anapc7.L; anaphase promoting complex subunit 7 L homeolog [KO:K03354 ]
446982 cdc16.L; cell division cycle 16 L homeolog [KO:K03353 ]
447196 ppp3ca.L; protein phosphatase 3, catalytic subunit, alpha isozyme L homeolog [KO:K04348 ] [EC:3.1.3.16 ]
447462 ppp2r5c.L; protein phosphatase 2 regulatory subunit B', gamma [KO:K11584 ]
447726 anapc7.S; anaphase promoting complex subunit 7 S homeolog [KO:K03354 ]
495076 ppp2r5e.S; protein phosphatase 2 regulatory subunit B', epsilon [KO:K11584 ]
495419 ccne2.S; uncharacterized protein LOC495419 [KO:K06626 ]
495970 rec8.L; REC8 meiotic recombination protein L homeolog [KO:K13054 ]
496247 anapc11.L; anaphase promoting complex subunit 11 L homeolog [KO:K03358 ]
595046 anapc10.L; uncharacterized protein LOC595046 [KO:K03357 ]
733440 fbxo43.S; uncharacterized protein LOC733440 [KO:K10318 ]
734319 anapc10.S; anaphase promoting complex subunit 10 S homeolog [KO:K03357 ]
734470 cpeb1.S; cytoplasmic polyadenylation element-binding protein 1-B [KO:K02602 ]
734526 cul1.L; uncharacterized protein LOC734526 [KO:K03347 ]
734832 anapc15.L; anaphase-promoting complex subunit 15B [KO:K25228 ]
779325 anapc5.L; anaphase promoting complex subunit 5 L homeolog [KO:K03352 ]
Compound C01245 D-myo-Inositol 1,4,5-trisphosphate
Reference Authors Haccard O, Jessus C
Title Oocyte maturation, Mos and cyclins--a matter of synthesis: two functionally redundant ways to induce meiotic maturation.
Journal Reference Authors Crane R, Gadea B, Littlepage L, Wu H, Ruderman JV
Title Aurora A, meiosis and mitosis.
Journal Reference Authors Perdiguero E, Nebreda AR
Title Regulation of Cdc25C activity during the meiotic G2/M transition.
Journal Reference Authors Perry JA, Kornbluth S
Title Cdc25 and Wee1: analogous opposites?
Journal Reference Authors Jessus C, Ozon R
Title How does Xenopus oocyte acquire its competence to undergo meiotic maturation?
Journal Reference Authors Revenkova E, Jessberger R
Title Shaping meiotic prophase chromosomes: cohesins and synaptonemal complex proteins.
Journal Reference Authors Belloc E, Pique M, Mendez R
Title Sequential waves of polyadenylation and deadenylation define a translation circuit that drives meiotic progression.
Journal Reference Authors Pesin JA, Orr-Weaver TL
Title Regulation of APC/C activators in mitosis and meiosis.
Journal Reference Authors Tang W, Wu JQ, Guo Y, Hansen DV, Perry JA, Freel CD, Nutt L, Jackson PK, Kornbluth S
Title Cdc2 and Mos regulate Emi2 stability to promote the meiosis I-meiosis II transition.
Journal Reference Authors Wu JQ, Kornbluth S
Title Across the meiotic divide - CSF activity in the post-Emi2/XErp1 era.
Journal Reference Authors Schmidt A, Rauh NR, Nigg EA, Mayer TU
Title Cytostatic factor: an activity that puts the cell cycle on hold.
Journal Reference Authors Vogt E, Kirsch-Volders M, Parry J, Eichenlaub-Ritter U
Title Spindle formation, chromosome segregation and the spindle checkpoint in mammalian oocytes and susceptibility to meiotic error.
Journal Reference Authors Perry AC, Verlhac MH
Title Second meiotic arrest and exit in frogs and mice.
Journal Reference Authors Tunquist BJ, Eyers PA, Chen LG, Lewellyn AL, Maller JL
Title Spindle checkpoint proteins Mad1 and Mad2 are required for cytostatic factor-mediated metaphase arrest.
Journal Reference Authors Hutchins JR, Dikovskaya D, Clarke PR.
Title Regulation of Cdc2/cyclin B activation in Xenopus egg extracts via inhibitory phosphorylation of Cdc25C phosphatase by Ca(2+)/calmodulin-dependent protein [corrected] kinase II.
Journal Related xla04914 Progesterone-mediated oocyte maturation
KO pathway 
