IAPG AS CR and PIGMOD center seminars in September 2015

Introduction to the group and its research

The live of all organisms including human insist on the integrity of information stored in DNA. DNA in the nucleus of the cell is organised into the individual chromosomes. All chromosomes (and mitochondrial DNA) form the genome. The cells possess very sophisticated mechanisms that recognize DNA damage and induce DNA repair – DNA damage response (DDR). Compromised DNA integrity is widely connected to cancer. However, compromised DNA integrity has also clear link to non-cancerous diseases such as infertility or neurological disorders.

In our group we use mainly quantitative fluorescence imaging techniques both in fixed and live cells to address the topic of genome integrity in mammalian oocytes in connection to infertility and neurological Huntington’s disease.

Our laboratory is an integral part of Pigmod Center supported by the project Experimental Animal Models (EXAM).

Research

Chromosome dynamics and integrity in female meiosis

This research interest originates from the existence of the two greatly distinct cell lines in animals: germ cells and somatic cells. They have significantly different demands for the genetic stability. The germ lines must ensure transmission of the genetic information to the offsprings and must be very effective in the DNA integrity maintenance. In somatic cells, DNA repair is a compromise between growth speed, cancer risk and also the cost for DNA repair.

Until now a great effort was put into the research of chromosome segregation in female meiosis (oocytes). However, the correct chromosome segregation is the only one part of protection of the genome integrity. Also DNA repair of lesions such as double and single strand DNA breaks, crosslink DNA and cell cycle checkpoint outside anaphase are clearly very important, but largely unknown in germ line (oocytes and early embryos).  DNA damage can arise from exogenous attacks such radiation but also from own basic metabolism (oxygen radicals) or DNA metabolism (replication, transcription).

In mammalian oocytes we focus both on the mechanism of chromosome segregation as well as on DNA damage response (DDR) on the DNA double strand breaks (DSB). Correct chromosome segregation is connected to normal cell cycle progression, normal spindle formation and functional spindle assembly checkpoint (SAC). We investigate signalling pathways that control these critical cellular processes. In the case of DSB we are trying to address the questions how are DSB recognized during meiotic maturation and how do oocytes deal with them? We are also interested in a potential link between DSB and whole chromosome segregation problem.

DNA damage response in neurological Huntington’s disease

The connection of DNA damage to cancer is well known. However neurological disorders, for example Huntington’s disease, are also associated with DNA damage and compromise DNA repair, although they have completely different impact for patients in comparison to cancer. Very interestingly, it is known from records that patients with Huntington’s disease have significantly lower cancer incidences. It provokes a question, how it is possible that DNA damage can lead to two completely different problems: cancer or neurodegeneration? We are interested in DSB response in cells compromised by the presence of mutated Huntingtin that is causative for Huntington’s disease.  In this research topic we are working in close collaboration with the Laboratory of Cell Regeneration and Plasticity at our institute. This laboratory created transgenic minipig of Huntington’s disease. This model provides change to better address progressive character of Huntington’s disease (including DSB accumulation) in comparison to accelerated and short-time living mouse models such R6/2. Our goal is understand problems with DSB response in Huntington’s disease and help to use this knowledge both for diagnostic and therapeutic purpose.

Live cell imaging gallery

Movie 1 – Mouse primary non-cancerous cell expressing H2B-mCHERRY (red) and PCNA-GFP (green) from transfected recombinant mRNA. Punctuated green signal marks progression through S-phase (DNA replication). Note for defective chromosome segregation in mitosis. [movie download]

Movie 2 – Mouse oocyte expressing H2B-mCHERRY (red) and MAP4-GFP (green) after mRNA microinjection progresses through meiotic maturation. Spindle formation, chromosome segregation and 1^st polar body extrusion are visible. [movie download]

Movie 3 – Mouse oocyte from transgenic CAG::H2B-EGFP mouse stained with fluorogenic compound SiR tubulin for microtubule visualization. Chromosomes (H2B) are pseudocolored by red, microtubules are green. In contrast to Movie 2, oocyte was only vitally stained by SiR tubulin without any mRNA microinjection. [movie download]

Movie 4 – Defective chromosome segregation (red) in oocyte after induction of double strand DNA breaks using radiomimetic drug Neocarcinostation (NCS) in prophase I (see also Movie 5). Oocyte is from transgenic CAG::H2B-EGFP mouse strain. [movie download]

Movie 5 – 3D projection of the nucleus of fixed mouse oocytes in prophase I after induction of double strand DNA breaks (DSBs) using radiomimetic drug Neocarcinostatin (NCS). DNA is stained by DAPI (blue), DSBs are visible as yellow dots for localization of DSB markers gH2AX (green) and MDC1 (red) to the site of DSB. [movie download]

Publications

Baran V, Brzakova A, Rehak P, Kovarikova V, Solc P. PLK1 regulates spindle formation kinetics and APC/C activation in mouse zygote. Zygote. 2015 Jul 15:1-8.

Kovarikova V, Burkus J, Rehak P, Brzakova A, Solc P, Baran V. Aurora kinase A is essential for correct chromosome segregation in mouse zygote. Zygote. 2015 Jul 15:1-12.

Solc P, Kitajima TS, Yoshida S, Brzakova A, Kaido M, Baran V, Mayer A, Samalova P, Motlik J, Ellenberg J. Multiple Requirements of PLK1 during Mouse Oocyte Maturation. PLoS One. 2015 Feb 6;10(2):e0116783.

Chalupnikova K, Solc P, Sulimenko V, Sedlacek R, Svoboda P. An oocyte-specific ELAVL2 isoform is a translational repressor ablated from meiotically competent antral oocytes. Cell Cycle. 2014;13(7):1187-200.

Baran V, Solc P, Kovarikova V, Rehak P, Sutovsky P. Polo-like kinase 1 is essential for the first mitotic division in the mouse embryo. Mol Reprod Dev. 2013 Jul;80(7):522-34.

Solc P, Baran V, Mayer A, Bohmova T, Panenkova-Havlova G, Saskova A, Schultz RM, Motlik J. Aurora kinase A drives MTOC biogenesis but does not trigger resumption of meiosis in mouse oocytes matured in vivo. Biol Reprod. 2012 Oct 11;87(4):85.

Kaláb P, Solc P, Motlík J. The role of RanGTP gradient in vertebrate oocyte
maturation. Results Probl Cell Differ. 2011;53:235-67.

Solc P, Schultz RM, Motlik J. Prophase I arrest and progression to metaphase I in mouse oocytes: comparison of resumption of meiosis and recovery from G2-arrest in somatic cells. Mol Hum Reprod. 2010 Sep;16(9):654-64.

Kalous J, Kubelka M, Solc P, Susor A, Motlík J. AKT (protein kinase B) is implicated in meiotic maturation of porcine oocytes. Reproduction. 2009 Oct;138(4):645-54.

Saskova A, Solc P, Baran V, Kubelka M, Schultz RM, Motlik J. Aurora kinase A controls meiosis I progression in mouse oocytes. Cell Cycle. 2008 Aug;7(15):2368-76.

Solc P, Saskova A, Baran V, Kubelka M, Schultz RM, Motlik J. CDC25A phosphatase controls meiosis I progression in mouse oocytes. Dev Biol. 2008 May 1;317(1):260-9.

Kalous J, Solc P, Baran V, Kubelka M, Schultz RM, Motlik J. PKB/AKT is involved in resumption of meiosis in mouse oocytes. Biol Cell. 2006 Feb;98(2):111-23.

Contacts

Laboratory of DNA integrity
Inst. of Animal Physiology and Genetics AS CR
Rumburska 89
277 21 Libechov
Czech Republic

group leader:
Petr Solc, Ph.D
petr.solc@gmail.com,
phone: +420 315 639 561, fax: +420 315 639 510