BSCB Newsletter, Summer 2005

BSCB/BSDB Joint Spring Meeting
Warwick University, 6-9 April 2005

mRNA localization
Neural stem cells
Polarized Secretion of Endocytic Organelles
Neuronal transmitters in health and disease
Asymmetric Cell Division
Cell Biology of behaviour
Micro-RNAs
Regulation of Cell Death
Mitosis
Hooke Medal Lecture
Lunchtime discussions: Women in Cell Biology and Careers in Biological Sciences

Asymmetric Cell Division

The session on asymmetric cell division was chaired by Jurgen Knoblich (IMP, Vienna), who started by talking about polarization of recycling endosomes during asymmetric cell division in the Drosophila nervous system. The hallmark of asymmetric cell division is segregation of cell fate determinants, the first of which to be identified was Numb. In the endocytic pathway, recycling endosomes are generated and accumulate around the centrosome of only one of the daughter cells. Rab11 is the marker for these recycling endosomes and is suppressed in cells that do not inherit Numb.  Rab11 binds Nuf, a centrosomal protein that binds and accumulates on only one of the centrosomes. Nuf and Numb act redundantly in asymmetric cell division.

Rita Sousa-Nunes (King's College, London) described a mutant obtained in a screen to identify new genes involved in the asymmetric division of the Drosophila neuroblast. This mutant has the intriguing phenotype of enhanced detection of centrosomal Miranda.  Continuing the studies on Drosophila, Francois Schweisguth (Ecole Normale Superieure, Paris) spoke about Neuralized, which, along with Numb, regulates Notch-mediated binary fate decisions. Bearded is a partner of Neuralized; overexpression and deletion experiments suggest that negative regulation of Neuralized by Bearded is at least partly responsible for the spatially restricted distribution of Delta (Notch ligand).

Arwen Wilcock (School of Life Sciences, Dundee) outlined a strategy to build extensive maps of cell lineage using electroporation of the spinal cord of chick embryos with GFP tubulin, followed by time-lapse 3D imaging.  After the coffee break, Pierre Gonczy (ISREC, Switzerland) described the importance of G protein signalling pathways for asymmetric cell division in C. elegans embryos.

Finally, Magda Zernicka-Goetz (Gurdon Institute, Cambridge) presented a non-invasive lineage tracing study of the early mouse embryo. The aim is to determine whether development of blastocyst pattern shows any correlation with the orientation and order of the second cleavage divisions that result in specific positioning of blastomeres at the 4-cell stage.  The results suggest that the spatial arrangement of individual 4-cell stage blastomeres and the order in which they are generated correlate with blastocyst pattern in the mouse embryo.

Teresa Barros
The Wellcome Trust/Cancer Research UK Gurdon Institute
University of Cambridge.
t.barros@gurdon.cam.ac.uk