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CHANGES IN THE RIBOSOME CONTENT, PRINCIPAL MICROSOMAL PROTEIN COMPOSITION, AND SECRETORY CHARACTER OF MAMMARY EPITHELIAL ROUGH ENDOPLASMIC RETICULUM DURING DIFFERENTIATION : Evidence that Messenger RNAs Specific for Milk Proteins are Incorporated into Rough Endoplasmic Reticulum Formed De Novo after Parturition

The equilibrium density distribution, protein composition, and secretory character of mouse mammary epithelial rough microsomes have been determined during differentiation. The density range exhibited by the rough microsomes broadens during mammary development; rough microsomes within the 1.25–1.29...

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Detalles Bibliográficos
Autores principales: Slaby, Frank, Brown, Carolyn
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1974
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2109303/
https://www.ncbi.nlm.nih.gov/pubmed/4836386
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author Slaby, Frank
Brown, Carolyn
author_facet Slaby, Frank
Brown, Carolyn
author_sort Slaby, Frank
collection PubMed
description The equilibrium density distribution, protein composition, and secretory character of mouse mammary epithelial rough microsomes have been determined during differentiation. The density range exhibited by the rough microsomes broadens during mammary development; rough microsomes within the 1.25–1.29 g/ml density range appear soon after conception and then within the 1.30–1.34 range after the onset of lactation. The appearance of these denser microsomes represents the progressive increase of the average ribosome content of the rough endoplasmic reticulum (ER) during gestation and lactation. Fractionation of rough microsomal proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis reveals that two proteins, having molecular weights of 57,000 and 76,000, occur to a significant extent only during lactation and are then most prominent in the very dense rough microsomes of the 1.30–1.34 range. Nascent polypeptide chains discharged (by incubation with puromycin) from 17-days lactation rough microsomes in either the 1.21–1.29 or 1.30–1.34 density range are distributed equally between the intra- and extravesicular compartments. Whereas 36% of the chains are discharged intravesicularly from 1-day lactation rough microsomes in the 1.30–1.34 range, only 25% are so discharged from those in the 1.21–1.29 range. The results indicate (a) that there is no correlation between the relative levels in lactation rough microsomes of the two microsomal proteins which become prominent during lactation and the extent of secretory activity and (b) that for a short period after parturition the rough ER elements bearing high surface densities of ribosomes have a greater proportion of ribosomes synthesizing milk proteins than the rough ER elements with moderate ribosome densities.
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spelling pubmed-21093032008-05-01 CHANGES IN THE RIBOSOME CONTENT, PRINCIPAL MICROSOMAL PROTEIN COMPOSITION, AND SECRETORY CHARACTER OF MAMMARY EPITHELIAL ROUGH ENDOPLASMIC RETICULUM DURING DIFFERENTIATION : Evidence that Messenger RNAs Specific for Milk Proteins are Incorporated into Rough Endoplasmic Reticulum Formed De Novo after Parturition Slaby, Frank Brown, Carolyn J Cell Biol Article The equilibrium density distribution, protein composition, and secretory character of mouse mammary epithelial rough microsomes have been determined during differentiation. The density range exhibited by the rough microsomes broadens during mammary development; rough microsomes within the 1.25–1.29 g/ml density range appear soon after conception and then within the 1.30–1.34 range after the onset of lactation. The appearance of these denser microsomes represents the progressive increase of the average ribosome content of the rough endoplasmic reticulum (ER) during gestation and lactation. Fractionation of rough microsomal proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis reveals that two proteins, having molecular weights of 57,000 and 76,000, occur to a significant extent only during lactation and are then most prominent in the very dense rough microsomes of the 1.30–1.34 range. Nascent polypeptide chains discharged (by incubation with puromycin) from 17-days lactation rough microsomes in either the 1.21–1.29 or 1.30–1.34 density range are distributed equally between the intra- and extravesicular compartments. Whereas 36% of the chains are discharged intravesicularly from 1-day lactation rough microsomes in the 1.30–1.34 range, only 25% are so discharged from those in the 1.21–1.29 range. The results indicate (a) that there is no correlation between the relative levels in lactation rough microsomes of the two microsomal proteins which become prominent during lactation and the extent of secretory activity and (b) that for a short period after parturition the rough ER elements bearing high surface densities of ribosomes have a greater proportion of ribosomes synthesizing milk proteins than the rough ER elements with moderate ribosome densities. The Rockefeller University Press 1974-06-01 /pmc/articles/PMC2109303/ /pubmed/4836386 Text en Copyright © 1974 by The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Article
Slaby, Frank
Brown, Carolyn
CHANGES IN THE RIBOSOME CONTENT, PRINCIPAL MICROSOMAL PROTEIN COMPOSITION, AND SECRETORY CHARACTER OF MAMMARY EPITHELIAL ROUGH ENDOPLASMIC RETICULUM DURING DIFFERENTIATION : Evidence that Messenger RNAs Specific for Milk Proteins are Incorporated into Rough Endoplasmic Reticulum Formed De Novo after Parturition
title CHANGES IN THE RIBOSOME CONTENT, PRINCIPAL MICROSOMAL PROTEIN COMPOSITION, AND SECRETORY CHARACTER OF MAMMARY EPITHELIAL ROUGH ENDOPLASMIC RETICULUM DURING DIFFERENTIATION : Evidence that Messenger RNAs Specific for Milk Proteins are Incorporated into Rough Endoplasmic Reticulum Formed De Novo after Parturition
title_full CHANGES IN THE RIBOSOME CONTENT, PRINCIPAL MICROSOMAL PROTEIN COMPOSITION, AND SECRETORY CHARACTER OF MAMMARY EPITHELIAL ROUGH ENDOPLASMIC RETICULUM DURING DIFFERENTIATION : Evidence that Messenger RNAs Specific for Milk Proteins are Incorporated into Rough Endoplasmic Reticulum Formed De Novo after Parturition
title_fullStr CHANGES IN THE RIBOSOME CONTENT, PRINCIPAL MICROSOMAL PROTEIN COMPOSITION, AND SECRETORY CHARACTER OF MAMMARY EPITHELIAL ROUGH ENDOPLASMIC RETICULUM DURING DIFFERENTIATION : Evidence that Messenger RNAs Specific for Milk Proteins are Incorporated into Rough Endoplasmic Reticulum Formed De Novo after Parturition
title_full_unstemmed CHANGES IN THE RIBOSOME CONTENT, PRINCIPAL MICROSOMAL PROTEIN COMPOSITION, AND SECRETORY CHARACTER OF MAMMARY EPITHELIAL ROUGH ENDOPLASMIC RETICULUM DURING DIFFERENTIATION : Evidence that Messenger RNAs Specific for Milk Proteins are Incorporated into Rough Endoplasmic Reticulum Formed De Novo after Parturition
title_short CHANGES IN THE RIBOSOME CONTENT, PRINCIPAL MICROSOMAL PROTEIN COMPOSITION, AND SECRETORY CHARACTER OF MAMMARY EPITHELIAL ROUGH ENDOPLASMIC RETICULUM DURING DIFFERENTIATION : Evidence that Messenger RNAs Specific for Milk Proteins are Incorporated into Rough Endoplasmic Reticulum Formed De Novo after Parturition
title_sort changes in the ribosome content, principal microsomal protein composition, and secretory character of mammary epithelial rough endoplasmic reticulum during differentiation : evidence that messenger rnas specific for milk proteins are incorporated into rough endoplasmic reticulum formed de novo after parturition
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2109303/
https://www.ncbi.nlm.nih.gov/pubmed/4836386
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AT browncarolyn changesintheribosomecontentprincipalmicrosomalproteincompositionandsecretorycharacterofmammaryepithelialroughendoplasmicreticulumduringdifferentiationevidencethatmessengerrnasspecificformilkproteinsareincorporatedintoroughendoplasmicreticulumformeddenovoa