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The relationship between polyribosomal and latent membrane-bound messenger ribonucleoprotein particles in Artemia
Abstract:
Polysomal messenger ribonucleoprotein (mRNP) particles from developing Artemia cysts were isolated, characterized and compared with latent membrane-bound mRNP particles isolated from dormant cysts. The polyribosomal mRNP particles sedimented between 25-35 S in a sucrose gradient and had a buoyant density of 1.33 g/cm3 in Cs2So4. Latent particles had a higher sedimentation coefficient and lower buoyant density. The poly(A) + RNA in the two kinds of particles was comparable in size, 10-20 S. The protein composition of the particles, as determined by electrophoresis, was different. Polyribosomal particles contained 9 major and 6 minor proteins; a 72 k poly(A)-associated protein was present. Latent particles were characterized by a complex protein pattern ranging in apparent mol. wt between 14,000-140,000. Some proteins with similar molecular weight and isoelectric point were probably common to both kinds of particles.
Insights
Messenger ribonucleoprotein (mRNP) particles from developing and dormant Artemia cysts differ in protein composition. These findings reveal distinct mRNP structures crucial for developmental transitions in Artemia.
Area of Science:
- Biochemistry
- Molecular Biology
- Developmental Biology
Background:
- Messenger ribonucleoprotein (mRNP) particles are key regulators of gene expression.
- Artemia cysts undergo significant developmental transitions from dormancy to development, involving changes in gene expression.
Purpose of the Study:
- To isolate and characterize polysomal mRNP particles from developing Artemia cysts.
- To compare these with latent membrane-bound mRNP particles from dormant cysts.
- To elucidate differences in their physical properties and protein composition.
Main Methods:
- Isolation and characterization of mRNP particles using sucrose gradient sedimentation and buoyant density centrifugation in Cs2SO4.
- Analysis of poly(A)+ RNA size by electrophoresis.
- Determination of protein composition using electrophoresis.
Main Results:
- Polysomal mRNP particles from developing cysts sedimented at 25-35 S with a buoyant density of 1.33 g/cm3.
- Latent mRNP particles from dormant cysts exhibited a higher sedimentation coefficient and lower buoyant density.
- Poly(A)+ RNA size was similar (10-20 S) in both particle types, but protein composition differed significantly, with latent particles showing a more complex protein pattern.
Conclusions:
- Developing and dormant Artemia cysts possess distinct mRNP particle populations.
- Differences in mRNP particle composition likely play a role in regulating gene expression during developmental transitions.