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Nuclear colocalization of c-myc protein and hsp70 in cells transfected with human wild-type and mutant c-myc genes

Henriksson, M; Classon, M; Axelson, H LU ; Klein, G and Thyberg, J (1992) In Experimental Cell Research 203(2). p.94-383
Abstract

Using immunofluorescence and electron microscopy we have studied the localization of wild-type and mutant c-myc proteins transiently expressed in CV-1 cells. In agreement with our previous observations, wild-type c-myc protein accumulated in large amorphous globules in the nucleus. All mutant proteins tested accumulated in the nucleus as well, but gave rise to morphologically different inclusion bodies. Many small globules appeared in cells transfected with D145-262 (deletion of amino acids 145-262), while cells transfected with D371-412 or D414-433 generated structures looking like a fine network or like beads on a string. In addition, a particulate cytoplasmic staining appeared in some cells transfected with the wild-type gene and in... (More)

Using immunofluorescence and electron microscopy we have studied the localization of wild-type and mutant c-myc proteins transiently expressed in CV-1 cells. In agreement with our previous observations, wild-type c-myc protein accumulated in large amorphous globules in the nucleus. All mutant proteins tested accumulated in the nucleus as well, but gave rise to morphologically different inclusion bodies. Many small globules appeared in cells transfected with D145-262 (deletion of amino acids 145-262), while cells transfected with D371-412 or D414-433 generated structures looking like a fine network or like beads on a string. In addition, a particulate cytoplasmic staining appeared in some cells transfected with the wild-type gene and in cells transfected with mutants D145-262 or D414-433. Since the c-myc protein has been reported to stimulate expression of exogenous hsp70 protein, we also examined the intracellular distribution of hsp70 in the transfected cells. Double immunofluorescence microscopy revealed that hsp70 codistributed with the c-myc protein in distinct globules in the nucleus of many but not all myc-positive cells. However, the levels of hsp70 transcripts were not significantly raised compared to nontransfected and vector-transfected cells. Likewise, the levels of hsp70 protein did not vary significantly. These findings indicate that overexpression of c-myc stimulates translocation of preexisting hsp70 from the cytoplasm into the nucleus, rather than influencing hsp70 expression. Conceivably, this may represent one of several mechanisms whereby the cell deals with excessive amounts of c-myc protein.

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author
organization
publishing date
type
Contribution to journal
publication status
published
keywords
Animals, Cell Line, Cell Nucleus, Cytoplasm, Genes, myc, Heat-Shock Proteins, Humans, Microscopy, Electron, Microscopy, Fluorescence, Mutation, Proto-Oncogene Proteins c-myc, Transfection
in
Experimental Cell Research
volume
203
issue
2
pages
12 pages
publisher
Academic Press
external identifiers
  • Scopus:0027074952
ISSN
0014-4827
DOI
10.1016/0014-4827(92)90012-W
language
English
LU publication?
yes
id
c6c7797b-ea8e-46b7-a8fe-857e941af951
date added to LUP
2016-08-09 09:20:05
date last changed
2016-11-14 09:42:59
@misc{c6c7797b-ea8e-46b7-a8fe-857e941af951,
  abstract     = {<p>Using immunofluorescence and electron microscopy we have studied the localization of wild-type and mutant c-myc proteins transiently expressed in CV-1 cells. In agreement with our previous observations, wild-type c-myc protein accumulated in large amorphous globules in the nucleus. All mutant proteins tested accumulated in the nucleus as well, but gave rise to morphologically different inclusion bodies. Many small globules appeared in cells transfected with D145-262 (deletion of amino acids 145-262), while cells transfected with D371-412 or D414-433 generated structures looking like a fine network or like beads on a string. In addition, a particulate cytoplasmic staining appeared in some cells transfected with the wild-type gene and in cells transfected with mutants D145-262 or D414-433. Since the c-myc protein has been reported to stimulate expression of exogenous hsp70 protein, we also examined the intracellular distribution of hsp70 in the transfected cells. Double immunofluorescence microscopy revealed that hsp70 codistributed with the c-myc protein in distinct globules in the nucleus of many but not all myc-positive cells. However, the levels of hsp70 transcripts were not significantly raised compared to nontransfected and vector-transfected cells. Likewise, the levels of hsp70 protein did not vary significantly. These findings indicate that overexpression of c-myc stimulates translocation of preexisting hsp70 from the cytoplasm into the nucleus, rather than influencing hsp70 expression. Conceivably, this may represent one of several mechanisms whereby the cell deals with excessive amounts of c-myc protein.</p>},
  author       = {Henriksson, M and Classon, M and Axelson, H and Klein, G and Thyberg, J},
  issn         = {0014-4827},
  keyword      = {Animals,Cell Line,Cell Nucleus,Cytoplasm,Genes, myc,Heat-Shock Proteins,Humans,Microscopy, Electron,Microscopy, Fluorescence,Mutation,Proto-Oncogene Proteins c-myc,Transfection},
  language     = {eng},
  number       = {2},
  pages        = {94--383},
  publisher    = {ARRAY(0xd5a4f98)},
  series       = {Experimental Cell Research},
  title        = {Nuclear colocalization of c-myc protein and hsp70 in cells transfected with human wild-type and mutant c-myc genes},
  url          = {http://dx.doi.org/10.1016/0014-4827(92)90012-W},
  volume       = {203},
  year         = {1992},
}