The human gamete lab

Mariola Chacón Rodríguez (IP)


Research team

Mariola Chacón Rodríguez

Associate professor Cell Biology Department

About us

Students interested in a PhD research about fertility and chromosome segregation in human gametes in collaboration with a medicine reproductive clinic, please write to mchaconr@us.es. In parallel the candidate will work with the nematode C.elegans to unravel molecular mechanisms that cannot be studied in the human samples. The student should have a competitive grade mark in order to apply for funding.

My main research interest is to investigate the molecular mechanism underlying human oocyte aneuploidy. Aneuploidy arising through chromosome mis-segregation during meiosis is a major cause of infertility and inherited birth defects. Aneuploid embryos account for at least 10% of human pregnancies in young women. Today, parenthood occurs at older ages, and in women nearing the end of their reproductive lifespan, the incidence may exceed 50%.

Proteins that contribute to oocyte aneuploidy are therefore of central interest. Germinal Vesicle (GV) stage it is a very unknown stage, in spite of being the longest phase of the meiosis in human oocyte. Thus, in the lab we aim to decipher the architecture of chromosome at this stage as well as the proteins that accompany the chromosomes during meiosis resumption from GV stage to the metaphase II oocyte, so called mature egg. One of the recently described aneuploidy factor in the mice oocyte is CENP-V. CENP- V is involved in centromeric cohesion, chromosome alignment and segregation in HeLa cells.

CENP-V depleted cells die within 2-3 days. A previous work in mice show that around 40% of CENP-V deficient mice oocytes arrest at meiosis I and the 60% that proceed to metaphase II show high level of aneuploidy. CENP-V support correct chromosome segregation through the interaction to spindle microtubules. By contrast, preliminary experiments in human eggs show a huge difference in the localization of CENP-V compared to mouse oocytes, raising the question of whether CENP-V has a different role in human meiosis. This caveat suggests the need to translate the study of CENP-V to human eggs. The aim of the lab is to investigate the role of CENP- V in aneuploidy and ageing in human female meiosis. The potential use of CENP-V as a biomarker for IVF applications will be also explored.

However, understanding the basis for errors in human oocytes meiosis is hampered by limited access to the cells and by the fact that meiotic prophase in mammals occurs during embryogenesis. To overcome this limitation, in parallel to the human study, the role of CENP-V in the oocyte aneuploidy will be analyzed in Caenorhabditis elegans. The nematode is a model system to study meiotic prophase in which most of the molecular mechanisms are conserved to humans.

Collaborators

Dr. Tatiana García Muse, CABIMER-Universidad de Sevilla, Spain

Prof. Rolf Jessberger, MTZ- Technische Universität Dresden, Germany

Prof. Mary Herbert, Newcastle University, UK

Dr. Dr. Manuel Fernández, director of Clínica Vida, Sevilla

STUDENTS ARE WELLCOME!

Please write to mchaconr@us.es if you are an enthusiastic and chromosome lover student!

Departamento de Biología Celular

Facultad de Biología. Universidad de Sevilla. Avda. Reina Mercedes, 6. 41012 - Sevilla.

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