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Measuring Cation Transport by Na,K- and H,K-ATPase in Xenopus Oocytes by Atomic Absorption Spectrophotometry: An Alternative to Radioisotope Assays
12:48

Measuring Cation Transport by Na,K- and H,K-ATPase in Xenopus Oocytes by Atomic Absorption Spectrophotometry: An Alternative to Radioisotope Assays

Published on: February 19, 2013

Protein kinase activity associated with stored messenger ribonucleoprotein particles of Xenopus oocytes

A Cummings1, J Sommerville

  • 1Department of Biology, University of St. Andrews, Scotland.

The Journal of Cell Biology
|July 1, 1988
PubMed

Insights

Protein kinase and mRNA-binding phosphoproteins are integral components of Xenopus oocyte messenger RNP (mRNP) particles. These components associate with mRNP throughout oocyte development and early embryogenesis.

Area of Science:

  • Molecular and Developmental Biology
  • Xenopus laevis oocyte biology
  • mRNA storage and translation regulation

Background:

  • Oocytes accumulate substantial mRNA for early embryogenesis.
  • Stored mRNA is stabilized and translationally repressed within messenger RNP (mRNP) particles.
  • Phosphorylation of mRNA-binding proteins is crucial for protein-mRNA interactions.

Purpose of the Study:

  • To investigate the role and localization of protein kinase and phosphoproteins within mRNP particles during Xenopus oocyte development.
  • To understand the dynamic association of these components with mRNP throughout oogenesis and early embryogenesis.

Main Methods:

  • Biochemical fractionation of Xenopus oocyte extracts.
  • Sedimentation analysis (S values) to characterize mRNP particle complexes.
  • Assay of protein kinase activity and identification of mRNA-binding phosphoproteins.

Main Results:

  • Protein kinase and mRNA-binding phosphoproteins are intrinsic components of mRNP particles.
  • At early stages, free protein particles with kinase activity and phosphoproteins are abundant.
  • During peak mRNA accumulation, these components are in 40-80 S mRNP particles.
  • As ribosomes increase, mRNPs form 80-110 S blocked translation initiation complexes.

Conclusions:

  • Protein kinase and phosphoproteins are integral and dynamic components of Xenopus oocyte mRNP particles.
  • Their association with mRNP particles changes with developmental stage, correlating with mRNA accumulation and ribosome availability.
  • These findings provide insights into the regulation of mRNA storage and translation during early development.

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