Stage proposé par Marie-Hélène VERLHAC
Nom et adresse du Laboratoire ou de l’Unité : Centre Interdiscipilnaire de Recherche en Biologie,
Collège de France, 11 place Marcelin Berthelot, 75005 Paris
Téléphone : 01 44 27 10 82
Mail : marie-helene.verlhac@college-de-france.fr
Site internet : http://www.college-de-france.fr/site/en-cirb/verlhac__1.htm
Directeur du Laboratoire ou de l’Unité : Alain PROCHIANTZ
Intitulé de l ‘équipe d’accueil : Asymmetric Divisions in Oocytes
Responsable de l’équipe : Marie-Hélène VERLHAC
Résumé du thème de recherche de l’équipe (une dizaine de lignes maximum)
We are interested in understanding the basic processes that control asymmetric division in
oocytes, with a major emphasis on meiotic spindle assembly and positioning in the absence of
canonical centrosomes. Indeed most oocytes lose their centrioles during oogenesis through a
process that is largely not characterized. Aneuploidy is a leading cause of congenital birth
defects and miscarriage in humans. Most aneuploidies are due to errors in maternal meiosis
and the increase in maternal age is a powerful contributor to the occurrence of aneuploidy
(Hassold and Hunt 2001). We would like to test the hypothesis that spindle assembly and
positioning are somehow coupled in mouse oocytes and that the peculiar mode of spindle
assembly is responsible for the high error rate of female meiosis.
Titre du projet de stage :
Acentrosomal spindle pole shaping in oocytes
Prénom, NOM, téléphone et adresse e-mail du Responsable du stage: Marie-Emilie TERRET
(marie-emilie.terret@college-de-france.fr)
Projet de stage :
In most animal cells, bipolar mitotic spindle formation relies on centrosomes acting as major
microtubule organizing centers. At mitosis onset, duplicated centrosomes rapidly promote
spindle bipolarization (Toso 2009), defining spindle poles as well as the spindle axis along
which chromosome attachment and segregation will take place (for review Tanenbaum &
Medema 2011). Chromosome segregation in female meiosis I is unusual in that meiotic
spindle poles do not have centrioles, are not anchored to the cortex via astral microtubules,
therefore lack canonical centrosomes. Such an atypical organization raises the important
question of how force transmission, essential for correct chromosome segregation, is achieved
inside the female meiotic spindle. Oocytes excepted, most healthy cells possess one or two
canonical centrosomes, depending on their progression in the cell cycle (centrosome
duplication takes place in S-phase). However, many solid tumours harbour an excess of
centrosomes, which correlates with an increased rate of aneuploidy. In drosophila, the
presence of extra-centrosomes induces tumorigenesis (Basto 2008). Yet the presence of extracentrosomes challenges tumour development: multipolar mitosis induces high levels of
aneuploidy putting cell viability at risk (Ganem 2009). How can cancer cells achieve to
maintain a balance between extra-centrosome number and a certain degree of aneuploidy, yet
keep dividing? It appears that cancer cells cluster their extra-centrosomes prior to division
(Quintyne 2005). We have shown that proper spindle assembly in oocytes also requires the
sorting and coalescence of multiple acentriolar MTOCs (Breuer 2010), a process reminiscent
of extra-centrosomes clustering. We would like to study this process in greater details in the
oocyte. We will notably test the role of a minus-end directed motor Kinesin-14 (HSET). This
kinesin has been involved in the process of extra-centrosome clustering (Kwon 2008). Hurp
knock-out, as well as HSET knock-down by siRNA, do not affect mitosis. Therefore both
proteins are good therapeutic targets to specifically slow down cancer cell, but not somatic
cell, division (cancer cells that do not cluster their extra-centrosomes will eventually die). A
previous study, using anti-HSET antibody injection, has suggested that this kinesin is only
involved in meiosis II spindle assembly (Mountain 1999). More specific tools are now
available to re-investigate HSET function in meiosis (siRNA, Rescue, Gain of function..).
This study will be done in collaboration with Claire Walczak lab (Indiana University,
Bloomington), which provided all the tools to address HSET function in meiosis. We will also
assess HSET localisation and function in Hurp knock-out mice as well as in oocytes mutant
for NuMA (Kolano 2012). This way we can test potential interactions between these two
MAPs and the HSET motor in meiotic spindle assembly and MTOCs sorting to the poles.
Techniques mises en œuvre par le stagiaire : oocyte collection and culture, Immunocytochemistry,
Immunotransfer, molecular biology, in vivo imaging using spinning disk confocal microscopy.
Publications du Responsable de stage au cours des 5 dernières années :
Original articles:
Kolano A., Brunet S., Silk A.D., Cleveland D.W. and Verlhac M.-H. 2012. Error prone mammalian female
meiosis from silencing the SAC without normal interkinetochore tension. PNAS, 109: E1858–E1867
Azoury J., Lee K.W., Georget V., Hikal P. and Verlhac M.-H. 2011. Symmetry breaking in mouse oocytes
requires transient F-actin meshwork destabilization. Development, 138:2903-2908
Breuer M., Kolano A., Kwon M., Li C.-C., Tsai T.-F., Pellman D., Brunet S. and Verlhac M.-H. 2010. HURP
permits MTOC sorting for robust meiotic spindle bipolarity, similar to extra-centrosome-clustering in cancer
cells. J. Cell Biol., 191:1251-1260.
Azoury J., Lee K.W., Georget V., Rassinier P., Leader B. and Verlhac M.-H. 2008. Spindle positioning in mouse
oocytes relies on a dynamic meshwork of actin filaments. Curr. Biol., 18: 1514-1519.
Brunet S., Dumont J., Lee K. W., Kinoshita K., Hikal P., Gruss O., Maro B. and Verlhac.M.-H. 2008. Meiotic
regulation of TPX2 protein levels governs cell cycle progression in mouse oocytes. PLos One, 3: e3338.
Dumont J., Petri S., Pellegrin F., Terret M.-E., Bohnsack M.T. , Rassinier P., Georget V., Kalab P., Gruss O. J.
and Verlhac M.-H. 2007. A centriole and RanGTP independent spindle assembly pathway in meiosis I of
vertebrate oocytes. J. Cell Biol., 176: 295-305.
Dumont J., Million K., Sunderland K., Rassinier P., Lim H., Leader B. and Verlhac M.-H. 2007. Formin-2 is
required for spindle migration and for the late steps of cytokinesis in mouse oocytes. Dev. Biol., 301: 254-265
Invited reviews :
A. Chaigne, M.-H.Verlhac, M.E. Terret. 2012. Spindle positioning in mammalian oocytes. Exp Cell Res, 318:
1442-1447.
J. Dumont and M.-H. Verlhac. 2012. Using FRET to study RanGTP gradients in live mouse oocytes. Chapter in
a book on Methods in Molecular Biology edited by Homer Hayden for Springer. 957: 107-120
M.-H. Verlhac and M. Breuer. 2012. Cytoskeletal correlates of oocyte meiotic divisions. Chapter in a book on
« Mammalian Oogenesis » edited by Maureen Pierce, Giovanni Coticchio and David Albertini for Springer.
Chapter 14: 195-207
M.-H. Verlhac. 2012. Meeting report of the minisymposium on “Meiosis and Oogenesis”. Mol Biol Cell, 23:
971-971
M.-H. Verlhac. 2011. Spindle positioning: going against the actin flow. Nat Cell Biol, 12: 1183-1185.
S. Brunet and M.-H. Verlhac. 2011. Positioning to get out of Meiosis: the asymmetry of division. Hum Reprod
Update, 17: 68-75.
M.-H. Verlhac, M.E. Terret, L. Pintard. 2010. Control of the oocyte-to-embryo transition by the ubiquitinproteolytic system in mouse and C. elegans. Curr Opin Cell Biol, 22: 758-763.
M.-H. Verlhac and K. W. Lee. 2010. Mechanisms of asymmetric division in metazoan meiosis. Book chapter
from the book « Oogenesis-The Universal Process», Wiley/Blackwell. Ch 11: 291-310.
Azoury J., Verlhac M.-H. and J. Dumont. 2009. Actin filaments, key players in the control of asymmetric
divisions in mouse oocytes. Biol. Cell, 101: 69-76.
A. C. Perry and M.-H. Verlhac. 2008. Second meiotic arrest and exit in frogs and mice. EMBO rep., 9: 246- 251.
M.-H. Verlhac and J. Dumont. 2008. Interactions between chromosomes, microfilaments and microtubules
revealed by the study of small GTPases in a big cell, the vertebrate oocyte. Mol. Cell. Endo., 282 :12-17.
Autres informations:
Etudiants actuellement en thèse ou en M2 dans l’équipe d’accueil.
M2 : Anchi Chang, resp : Marie-hélène Verlhac
Thèse : Agathe Chaigne (2° année, CDV), co-resp : Marie-Emilie Terret (CR1/INSERM)
Thèse : Malgorzata Luksza (3° année, CDV), co-resp : Stéphane Brunet (CR1/INSERM, HDR)
Etudiants ayant préparé ou soutenu leur thèse ou leur M2 dans l’équipe d’accueil au cours des
six dernières années.
Manuel Breuer, soutenance Janvier 2010, école doctorale CDV
Jessica Azoury, soutenance Sept 2010, école doctorale CDV
Cette proposition de stage s’adresse-t-elle spécifiquement à un étudiant scientifique, médecin
ou vétérinaire ou bien est-il ouvert à tous les profils ? ouvert à tous les profils
Ce sujet peut-il donner lieu à une thèse ? oui