Biología Celular y del Desarrollo
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GERM CELLS APOPTOSIS, DEVELOPMENT AND FUNCTION USING THE NEMATODE C. elegans AS A MODEL ORGANISM.
Our understanding in human biology has greatly improved thanks to studies made in model organisms. These model organisms, including invertebrates like flies and worms and, certain vertebrates such as fishes and mice, are easy to manipulate in the laboratory, but still exhibit all the essential features of more complex species. Thus, what we observe in studying in these simpler models can be extrapolate to higher organisms.
In our laboratory we are using the roundworm, Caenorhabditis elegans, as a model to study the function and development of germ cells. C. elegans is a small, free-living nematode (about 1 mm long when fully-grown) that feeds on bacteria and can be grown easily in the laboratory. We can visualize worm structures simply by viewing them through the microscope, due to the animalús transparency.
Additional advantages of this organism as a research model are its relatively quick developmental cycle and ability to self-propagate. Embryogenesis is completed in fourteen hours, and sexual maturity is reached in three days. The fully-grown adult C. elegans has 959 cells that are organized in layers of epidermis, intestine, excretory and reproductive systems, and nerve and muscle cells. The lineage of each of the C. elegans cells is clearly known and traceable thanks to its constant development.
The C. elegans genome is completely known, and shows 19,000 genes. RNAi is a commonly used technique in C. elegasn labs to understand gene function. Much progress has already been made through C. elegans research. In 2002 Nobel Prize in Medicine or Physiology (2002) was awarded to Sydney Brenner, John Sulston, and Robert Horvitz for their contributions to Developmental Biology, and the discovery of apoptosis using C. elegans as a model organism. In 2006, Craig Mello and Andy Fire were awarded with a Nobel Prize for the discovery of the RNAi mechanism using C. elegans as a model system.
We are using C. elegans as a model organism to understand germ cell biology. Germ cells are totipotencial, immortal and able to undergo meiosis. They are the founder cells of gametes and, as such, they carry forward the genotype of each individual, including all of its defects as well as desirable traits, into future generations. A molecular description of germ cell differentiation will lead to a better understanding of fertility, childhood diseases, germ-cell tumors and will help to develop more effective methods of contraception. Despite their importance we still have much to learn about how these cells function and how are they regulated. With the help of this model, C. elegans, we are pursuing this knowledge.
Otras actividades y distinciones
En el 2004 fue reconocida con una beca internacional del Programa "Mujeres en la Ciencia" de UNESCO/L´OREAL.
Ese mismo año fue profesora visitante de la Escuela de Medicina del Johns Hopkins en Baltimore en donde se especializó en la producción de transgénicos del C. elegans.
Grupo de trabajo
Laura Silvia Salinas Velázquez (Técnico Académico)
Emmanuel Villanueva Chimal (Estudiante de Doctorado)
Paulette Fernández Cardenas (Estudiante de Doctorado)
Gabriela Huelgas Morales (Estudiante de Doctorado)
Emilio Carranza García (Estudiante de Doctorado)
Andrea Isabel Flores Sánchez (Estudiante de Maestría)
Diego Ceballos Porta (Aspirante al Doctorado)
Instituto de Fisiología Celular (desde 2002)
Universidad Nacional Autónoma de México
Geraldine Seydoux (2004)
Escuela de Medicina de la Universidad Johns Hopkins, Baltimore, E.U.
T. KeithBlackwell (1998-2002)
Escuela de Medicina de la Universidad de Harvard, Boston, Massachusetts, E.U.
Doctorado en Ciencias Bioquímicas. (1998)
Facultad de Química. Universidad Nacional Autónoma de México, México
Licenciatura en Biología (1995)
Facultad de Ciencias. Universidad Nacional Autónoma de México, México
Germ cells apoptosis : Germ cells apoptosis is frequent in several organisms including mammals. In C. elegans fifty percent of germ cells are eliminated during oogenesis to maintain gonad homeostasis. Higher levels of germ cell apoptosis occur when animals are exposed to DNA damage, pathogens or different types of stress. The mechanism by which germ cells apoptosis is triggered is still unknown, and we are using a combination of Microarray and RNAi analysis to identify proteins involved in germ cell apoptosis. Technician: Silvia Salinas. Graduate student: Carlos Giovanni Silva, Laura Láscarez Lagunas and Emmanuel Villanueva Chimal.
Germ cell function and mantainance : Germ cells carry information for the next generations. All the necessary elements to preserve the germline, and to undergo embryogenesis are accumulated in the oocyte cytoplasm. Germ cell cytoplasm contains germ granules known as P granules, which are made of mRNA/protein complexes. We are interested in studying P granule components and their function. The RNA helicase VBH-1 is a P granule component that is essential for germline function. Some vbh-1(RNAi) animals die during embryogenesis and others developed into sterile adults. We are using a combination of Microarray and RNAi analysis to understand VBH-1 function. We are also using the Two Hybrid technique and inmunoprecipitation analysis to isolate proteins that interact with VBH-1, which will help us to elucidate its function. Technician: Silvia Salinas. Graduate student: Daniel Paz Gómez.
Última actualización: 30/03/2015