title: Actin messenger in maternal RNP particles from an insect embryo (Smittia spec., Chironomidae, Diptera).
abstract: Actin synthesis was observed in early embryos of the chironomid midgeSmittia spec. The criteria used to identify newly synthesized actin include comigration with purified actin in two-dimensional gel electrophoresis, and peptide mapping after limited proteolysis. Actin was also identified after in vitro translation of RNA or salt washed RNP-particles isolated from newly deposited eggs. While intact RNP-particles stimulated protein synthesis only poorly, the rate of synthesis increased considerably after partial or complete removal of proteins from RNP-particles. Actin was synthesized both during advanced stages of oogenesis and during early embryogenesis. In embryos during intravitelline cleavage actin synthesis was insensitive to inhibitors of transcription (actinomycin D, α-amanitin). Actin was found everywhere along the longitudinal axis of the embryo using a procedure which allowed simultaneous sectioning of a large number of embryos.
authors.affiliation: Department of Zoology, University of Texas at Austin, 78712, Austin, Texas, USA.
authors.forename: Herbert
authors.initials: H
authors.lastname: Jäckle
keywords: Actin synthesis; Insect embryogenesis; “Masked” mRNP-particles