TY - JOUR
T1 - Messenger ribonucleoprotein particles in unfertilized sea urchin eggs
AU - Kaumeyer, John F.
AU - Jenkins, Nancy A.
AU - Raff, Rudolf A.
N1 - Funding Information:
We thank Dr. Y. Chooi, Dr. D. E. Leister, and Dr. E. C. Raff for their critical readings of the manuscript, Dr. M. Nemer for helpful discussions, and Mrs. C. J. Huffman for skillful technical assistance. This work was supported by U.S.P.H.S. Grant HD06902. R.A.R. is the recipient of U.S.P.H.S. Career Development Award K04 HD47. N.A.J. is a predoctoral trainee in Molecular and Cell Biology supported by U.S.P.H.S. Award T32 GM07227, and J.F.K. is a predoctoral trainee in Genetics supported by N.I.H. Training Grant 82.
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 1978/4
Y1 - 1978/4
N2 - The properties of poly(A)-containing messenger ribonucleoprotein particles (mRNPs) from unfertilized sea urchin eggs isolated under various ionic conditions were studied. Poly(A)-containing RNPs of eggs sediment with a modal value of 60-65 S under all conditions used. However, buoyant densities vary strikingly with conditions of particle preparation. Deproteinized poly(A)-containing mRNA has an average molecular weight of about 1 × 106. RNPs prepared in 0.35 M Na+ in the absence of Mg2+ contain an average of 0.25 × 106 daltons of protein, while particles prepared in 0.05 M Na+ in the absence of Mg2+ contain 0.35 to 11 × 106 daltons of protein per RNA molecule. Particles prepared in 0.35 M Na+ plus 5 mM Mg2+ contain 1.4 × 106 daltons of protein suggesting that Mg2+ may be necessary for maintenance of RNP intergrity if high Na+ concentrations are used to prevent nonspecific RNA-protein interactions. Particles prepared in 0.35 M K+ contain 0.9 × 106 daltons of protein in both Mg2+ and EDTA. Mg2+ does not cause significant aggregation of particles, since the size of RNA extracted from RNPs is proportional to RNP sedimentation rate. Monovalent cation concentrations normally used in analysis of RNPs by sedimentation cause deproteinized poly(A)-containing RNA to sediment with abnormally high sedimentation coefficients, indicating that high sedimentation rates alone do not indicate that RNA is contained in an RNP.
AB - The properties of poly(A)-containing messenger ribonucleoprotein particles (mRNPs) from unfertilized sea urchin eggs isolated under various ionic conditions were studied. Poly(A)-containing RNPs of eggs sediment with a modal value of 60-65 S under all conditions used. However, buoyant densities vary strikingly with conditions of particle preparation. Deproteinized poly(A)-containing mRNA has an average molecular weight of about 1 × 106. RNPs prepared in 0.35 M Na+ in the absence of Mg2+ contain an average of 0.25 × 106 daltons of protein, while particles prepared in 0.05 M Na+ in the absence of Mg2+ contain 0.35 to 11 × 106 daltons of protein per RNA molecule. Particles prepared in 0.35 M Na+ plus 5 mM Mg2+ contain 1.4 × 106 daltons of protein suggesting that Mg2+ may be necessary for maintenance of RNP intergrity if high Na+ concentrations are used to prevent nonspecific RNA-protein interactions. Particles prepared in 0.35 M K+ contain 0.9 × 106 daltons of protein in both Mg2+ and EDTA. Mg2+ does not cause significant aggregation of particles, since the size of RNA extracted from RNPs is proportional to RNP sedimentation rate. Monovalent cation concentrations normally used in analysis of RNPs by sedimentation cause deproteinized poly(A)-containing RNA to sediment with abnormally high sedimentation coefficients, indicating that high sedimentation rates alone do not indicate that RNA is contained in an RNP.
UR - http://www.scopus.com/inward/record.url?scp=0018094145&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0018094145&partnerID=8YFLogxK
U2 - 10.1016/0012-1606(78)90133-1
DO - 10.1016/0012-1606(78)90133-1
M3 - Article
C2 - 565308
AN - SCOPUS:0018094145
SN - 0012-1606
VL - 63
SP - 266
EP - 278
JO - Developmental Biology
JF - Developmental Biology
IS - 2
ER -