The movement of proteins between host and transplanted nuclei in Amoeba proteus
The movement of proteins between host and transplanted nuclei in Amoeba proteus
This study has examined protein migration from a radioactively labelled amoeba nucleus transplanted into an unlabelled homophasic amoeba. Nuclei were transferred at three times in the cell cycle coinciding with: DNA synthesis, 4 hours after division; a peak of RNA synthesis, 25 hour; and a relative lull in synthetic activity, 43 hours. Individual amino acids were used to label different classes of nuclear proteins: leucine, valine and serine as 'general' protein labels; lysine and arginine - histones; and aspartic acid - non-histone proteins, (NHP). Migration from the donor nucleus was found to be greatest following the transfer of a 25 hour old aspartic acid labelled nucleus into an unlabelled amoeba, suggesting a possible relationship with RNA synthesis. Movement was least following the transfer of nuclei labelled with the basic amino acids. This suggested that the migratory proteins were non-histone proteins, and the histones were retained by the transplanted nuclei. Protein migration was reduced following actinomycin-D inhibition of RNA synthesis, suggesting the existence of two classes of migratory proteins. One type was associated with RNA synthesis, and was found mainly in the host cytoplasm. The second class was present in the host nucleus and migrated irrespective of RNA synthesis.Characterisation of these proteins by iso-electric focusing and SDS electrophoresis revealed that the host cytoplasmic proteins had iso-electric points (p2's) between 7.0 and 7.6 and a molecular weight range of between 9,350 - 110,000 Daltons. The proteins accumulated by the host nucleus had a pI range of 5.9 - 7.0, with the majority of the molecular weights within the range of 10,800 - 45,200 Daltons. It is suggested that the migration of the host cytoplasmic proteins was due to an involvement with RNA packaging and transport. The host nuclear proteins exhibited a shuttling character, probably functioning as regulators of nuclear activities.
University of Southampton
1980
Mills, Kenneth Ian
(1980)
The movement of proteins between host and transplanted nuclei in Amoeba proteus.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
This study has examined protein migration from a radioactively labelled amoeba nucleus transplanted into an unlabelled homophasic amoeba. Nuclei were transferred at three times in the cell cycle coinciding with: DNA synthesis, 4 hours after division; a peak of RNA synthesis, 25 hour; and a relative lull in synthetic activity, 43 hours. Individual amino acids were used to label different classes of nuclear proteins: leucine, valine and serine as 'general' protein labels; lysine and arginine - histones; and aspartic acid - non-histone proteins, (NHP). Migration from the donor nucleus was found to be greatest following the transfer of a 25 hour old aspartic acid labelled nucleus into an unlabelled amoeba, suggesting a possible relationship with RNA synthesis. Movement was least following the transfer of nuclei labelled with the basic amino acids. This suggested that the migratory proteins were non-histone proteins, and the histones were retained by the transplanted nuclei. Protein migration was reduced following actinomycin-D inhibition of RNA synthesis, suggesting the existence of two classes of migratory proteins. One type was associated with RNA synthesis, and was found mainly in the host cytoplasm. The second class was present in the host nucleus and migrated irrespective of RNA synthesis.Characterisation of these proteins by iso-electric focusing and SDS electrophoresis revealed that the host cytoplasmic proteins had iso-electric points (p2's) between 7.0 and 7.6 and a molecular weight range of between 9,350 - 110,000 Daltons. The proteins accumulated by the host nucleus had a pI range of 5.9 - 7.0, with the majority of the molecular weights within the range of 10,800 - 45,200 Daltons. It is suggested that the migration of the host cytoplasmic proteins was due to an involvement with RNA packaging and transport. The host nuclear proteins exhibited a shuttling character, probably functioning as regulators of nuclear activities.
This record has no associated files available for download.
More information
Published date: 1980
Identifiers
Local EPrints ID: 459144
URI: http://eprints.soton.ac.uk/id/eprint/459144
PURE UUID: 10046c47-bd8c-4103-af4e-01f3059916c3
Catalogue record
Date deposited: 04 Jul 2022 17:05
Last modified: 04 Jul 2022 17:05
Export record
Contributors
Author:
Kenneth Ian Mills
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics