Summary: The uneven division during the first cell cycle of C. elegans embryogenesis is illustrated as an example cell biology research. Images, movies, matching animations and bioclips are provided to help understand this phenomenon.
Image I is a one-cell C. elegans embryo (right after sperm enters oocyte). Image II is a 2-cell C. elegans embryo. An adult C. elegans is in image III. In a single-cell embryo, the difference in anterior and posterior is already established. In the 2-cell embryo these differenences are more pronounced (large vs small cells). In the adult worm, there are very distinct structures in the anterior versus posterior.
Helpful information for understanding the early C. elegans embryo
Basic components in embryoG
Animation and Bioclips of cell polarity & Cell division
From the phenomenon and cell polarity animation, polarizationG can be observed as the generation of two unequal-size daughter cells and the unequal distribution of cellular components in the two daughter cells, e.g.: components on cell membraneG (notice the distribution of the purple and orange lines).
1) What components are distributed differently?
2) How important is it to have the cellular components polarized?
3) What are the functions of the polarized cellular components?
4) What are the spatial and temporal relationship between the polarized and non-polarized components?
1. Images of 1-cell and 2-cell embryo: Kevin O’Connell, National Institute of Diabetes & Digestive & Kidney Diseases (NIDDK).
2. Image of the adult worm: Bob
Goldstein, The University of North Carolina at Chapel Hill
Bioclip: a self-contained animations with in-depth presentation of biology concepts to help convey the research focus of a laboratory.
Embryo: the early developmental stage of an organism (C. elegans in this case) after fertilization and before hatching.
Membrane: permeability barrier surrounding cells or organelles and consists of a phospholipids bilayer, together with associated membrane proteins.
Polarization: the action/process of establishing polarity.
Pro-nucleus: one of two haploid nuclei in a newly fertilized embryo (one maternal and one paternal). (The Cell – A Molecular Approach. Geoffrey M. Cooper 1997)
Zygote: a fertilized egg; diploid cell resulting from fusion of a male and female gamete. (Molecular Cell Biology/Harvey Lodish [et al.] – 4th)