A Freeze‐Sectioning Method for Preparation of the Detergent‐Resistant Cytoskeleton Identifies Stage‐Specific Cytoskeleal Proteins and Associated mRNA in Xenopus Oocytes and Embryos: Cytoskeleton/amphibian/mRNA

Proteins of the detergent‐resistant cytoskeleton fraction and the detergent‐soluble fraction from Xenopus oocytes and embryos are examined using a procedure which allows rapid and uniform extraction of tissues and large, single cells. SDS‐polyacrylamide gels reveal only a few prominent cytoskeletal proteins in the early embryo, however qualitatively different proteins begin to appear after gastrulation. Incorporation of [³⁵S]‐methionine into newly synthesized proteins indicates that there is synthesis and assembly of proteins into the cytoskeleton, but the amount remains low until after gastrulation. The use of nucleic acid probes for alpha‐tubulin and actin mRNA indicates that about 80% of these mRNAs in the oocyte and meiotically mature egg are bound to the detergent‐resistant cytoskeleton.