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Studies on rabbit reticulocyte ribosomes and polyribosomes and their relation to hemoglobin synthesis


Glowacki, Ellen Rose (1966) Studies on rabbit reticulocyte ribosomes and polyribosomes and their relation to hemoglobin synthesis. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/H4BA-4M16.


This dissertation is divided into three parts.

The first section is concerned with protein synthesis in cellfree systems from reticulocytes. The sub-cellular reticulocyte fractions, reagents, etc. have been examined for the presence of traces of ribonuclease, using. an assay based upon the loss of infectivity of RNA fran bacteriophage MS2. This assay is sensitive to 5 x 10-7 γ RNase/ml. In addition, the loss of synthetic capacity of an 80S ribosome on dissociation has been studied, and can be attributed to loss of messenger RNA when the monomer is separated into subunits. The presence of ribonuclease has been shown to be a major cause of polyribosome disintegration during cell-free protein synthesis.

The second section concerns the changes in ribosomes and polyribosomes which occur during the maturation of a reticulocyte into an erythrocyte. With increasing age, the cells lose a large proportion of the ribonucleoprotein, but the percentage of ribosomes present as polyribosomes is only slightly altered. The loss of hemoglobin synthesis on maturation is probably due to both the loss of total ribosomes and to the lessened specific activity of the polyribosomes.

The third section contains analytical ultracentrifugation data on 80S ribosomes, polyribosomes, and ribosomal RNA from reticulocytes. The 60s and 40s subunits, obtained by dissociation of the 80s particle with inorganic pyrophosphate, were also studied. The RNA from reticulocyte ribosomes has been examined under a variety of denaturing conditions, including dimethyl sulfoxide treatment, formaldehyde reaction and thermal denaturation. From these studies we can conclude that the 28S and 16S RNA's are single polynucleotide chains and are not made up of smaller RNA subunits hydrogen-bonded together.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Biochemistry
Degree Grantor:California Institute of Technology
Major Option:Biochemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Borsook, Henry (advisor)
  • Sinsheimer, Robert L. (co-advisor)
Thesis Committee:
  • Unknown, Unknown
Defense Date:11 March 1966
Record Number:CaltechTHESIS:02122016-082048849
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9558
Deposited By: Benjamin Perez
Deposited On:12 Feb 2016 18:52
Last Modified:21 Dec 2019 02:50

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