Microinjection of Rap2B protein or RNA induces rearrangement of pigment granules in Xenopus oocytes.


Journal Article

Rap2B, a member of the ras superfamily of low-molecular-mass GTP-binding proteins, induced a characteristic rearrangement of the pigment granules in Xenopus oocytes following its microinjection, resulting in numerous unpigmented spots on the animal hemisphere. This phenomenon, termed 'mottling', was also induced by microinjection of in vitro-transcribed Rap2B RNA or of purified recombinant Rap2A. Following the microinjection of Rap2B, more than 90% of the oocytes showed signs of mottling within 10 h. The time course of mottling paralleled the association of the recombinant Rap2B with an oocyte membrane fraction. Like other members of the ras superfamily, Rap2B possesses a C-terminal CAAX motif that serves as a signal for post-translational processing. Mutation of the cysteine residue in the CAAX motif to serine prevents the association of Rap2B with oocyte membranes, and also prevents mottling. This result suggests that post-translational processing of Rap2B is required for the observed effect. Mottling was blocked by boiling Rap2B prior to its microinjection or by co-injection of the cytoskeletal reagent phalloidin.

Full Text

Duke Authors

Cited Authors

  • Campa, MJ; Farrell, FX; Lapetina, EG; Chang, KJ

Published Date

  • May 15, 1993

Published In

Volume / Issue

  • 292 ( Pt 1) /

Start / End Page

  • 231 - 236

PubMed ID

  • 7684898

Pubmed Central ID

  • 7684898

International Standard Serial Number (ISSN)

  • 0264-6021

Digital Object Identifier (DOI)

  • 10.1042/bj2920231


  • eng

Conference Location

  • England