Snoods: A periodic network containing cytokeratin in the cortex of starfish oocytes

• Published in: Developmental biology Vol. 144; no. 2; pp. 240 - 247
• Main Authors: Schroeder, Thomas E., Otto, Joann J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.04.1991; Elsevier
• Subjects: Actin Cytoskeleton - ultrastructure; Animals; Biological and medical sciences; cytochemistry; cytokeratin; cytoplasm; Cytoskeleton - ultrastructure; Echinodermata; eggs; Fertilization; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Invertebrates; Keratins - physiology; Marine; meiosis; Microscopy, Electron; Microtubules - ultrastructure; Oocytes - ultrastructure; oogenesis; Pisaster ochraceus; Starfish - embryology; Asteroidea; Embryonic development; Cytokeratin; Echinodermata; Immunocytochemistry; Pisaster ochraceus; Microfilament; Cortical granulation; Marine environment; Keratin; Transmission electron microscopy; Cytoskeleton; Microtubule; Invertebrata; Oocyte
• ISSN: 0012-1606; 1095-564X
• DOI: 10.1016/0012-1606(91)90418-3

An extensive fibrous cytoskeletal component in the cortical cytoplasm of oocytes of the starfish Pisaster ochraceus reproducibly stains with anticytokeratin antibody and hence contains cytokeratin. The large-meshed network resembles a snood (hair net). Snood fibers form loops and branches throughout the cortex of a premeiotic oocyte, except at the animal pole where they emanate from a nonstaining zone surrounding the centrosomes. By immunofluorescence microscopy of isolated cortices and electron microscopy of isolated cortices and intact oocytes, snood fibers exhibit complex striations with a periodicity of ∼0.75 μm. Snoods are not colocalized with the cortical arrays of microtubules and are unaffected by drugs that disrupt microtubules or microfilaments. Stimulation of oocyte maturation by 1-methyladenine causes snoods to disappear, presumably by disassembly, about halfway to the time of germinal vesicle breakdown. They do not reappear during meiosis, fertilization, or development to the two-cell stage, and their functional importance, if any, during oogenesis or development remains to be elucidated.