CMMB 403 Lecture Notes - Lecture 15: Integral Membrane Protein, Actomyosin Ring, Nuclear Membrane
1 Dec 2018
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After 13th cell division, the embryo has about 6000 nuclei. A syncytium is a cell with many nuclei in a common cytoplasm, no cell membranes separate nuclei. Cellularization fo teh nuclei begins at cycle 13, when the cell membrane folds inward to enclose each nuclei in a cell, creating the cellular blastoderm which forms within 4 hours of fertilization. Maternal and zygotic mrna concentrations are correlated with cleavage. After cycle 13, the cellular blastoderm forms by ingression of cell membranes between nuclei. Pole cells (germ cell precursors) form in the posterior. Picture a: nuclei at the periphery of the embryo. Red stain in the nuclei is due to the presence of the kugelkern protein, which is one of the earliest proteins made from the zygotic nuclei. Kugelkern protein is essential for nuclear elongation. As cellularization proceeds, nuclear envelope elongates, and membranes grow down so it can. Depicts embryo that was treated with nocadozole to disrupt microtubules.
