Expression of a developmentally regulated cross-linking intermediate filament-associated protein (IFAPa-400) during the replacement of vimentin for desmin in muscle cell differentiation

1991 ◽  
Vol 98 (2) ◽  
pp. 251-260 ◽  
Author(s):  
L.J. Cossette ◽  
M. Vincent

Myogenic and neurogenic tissues of the chick embryo transiently express IFAPa-400, a high molecular weight protein that colocalizes and is copurified with intermediate filaments. Using monoclonal antibody F51H2 to identify it, we carried out immunoelectron microscopy experiments on whole-mount chick embryo cells and showed that IFAPa-400 was localized at crossing points of intermediate filaments. Also, immunoblot experiments with F51H2, anti-vimentin and anti-desmin antibodies demonstrated the complete disappearance of IFAPa-400 in those muscle cell types that change their vimentin content for desmin during embryogenesis. During in vitro myogenesis, the expression of IFAPa-400 was shown to be concurrent with the progressive replacement of vimentin by desmin in myoblasts. When long-term myotube cultures were maintained on a fibroblast-like cell layer, we observed the complete replacement of vimentin by desmin, followed by the disappearance of IFAPa-400 from the myotubes. These results suggest that IFAPa-400 might be involved in the reorganization of the intermediate filament network during muscle differentiation.

1995 ◽  
Vol 73 (9-10) ◽  
pp. 651-657 ◽  
Author(s):  
Marie Duval ◽  
Xiaoying Ma ◽  
Jean-Paul Valet ◽  
Michel Vincent

IFAPa-400, a 400-kDa developmentally regulated protein thought to be associated with intermediate filaments, has been purified from chick embryo hearts to investigate its interaction with vimentin and other IF proteins and to identify other cellular components to which this cytoskeletal protein associates. Previous studies suggested that this protein was associated with the vimentin-containing intermediate filament lattice of myoblasts and neuroblasts before their terminal differentiation, providing these cells with a particular intermediate filament cytoskeleton that could satisfy specific mechanical requirements during their intense morphogenetic activities. Although IFAPa-400 partially reassociated with vimentin and desmin in disassembly–reassembly experiments using crude IF preparations from chick embryo hearts, in vitro recombination of purified IFAPa-400 with vimentin and desmin failed to demonstrate any direct association. When purified IFAPa-400 was used as a probe in blot overlay assays, however, specific binding to vimentin and desmin was observed, providing the first evidence of a physical association between IFAPa-400 and intermediate filament proteins. The blot overlay experiments also demonstrated that IFAPa-400 binds to two unidentified polypeptides of 19 and 32 kDa. These results are thus consistent with the hypothesis that a structural lattice requiring a vimentin–IFAPa-400 combination constitutes the intermediate filament system of myogenic and neurogenic cells.Key words: cytoskeleton, intermediate filaments, intermediate filament associated proteins, vimentin, IFAPa-400.


Oncology ◽  
1986 ◽  
Vol 43 (3) ◽  
pp. 183-186 ◽  
Author(s):  
F.S. Liotti ◽  
M. Bodo ◽  
F. Pezzetti ◽  
P. Guerrieri ◽  
A.R. Menghini

1962 ◽  
Vol 115 (1) ◽  
pp. 245-251 ◽  
Author(s):  
Robert M. Dougherty ◽  
Herbert R. Morgan

Chick embryo fibroblasts infected in vitro with Rous sarcoma virus have properties similar to tumor cells when injected into virus-immune chickens. When such virus-transformed fibroblasts are injected into normal chickens, they apparently participate in the production of tumors independent of their release of virus and are thus apparently malignant in vivo.


Mouse embryo cells induced to differentiate with the demethylating agent 5- azacytidine represent an excellent model system to investigate the molecular control of development. Clonal derivatives of 10T1/2 cells that have become determined to the myogenic or adipogenic lineages can be isolated from the multipotential parental line after drug treatment. These determined derivatives can be cultured indefinitely and will differentiate into end-stage phenotypes on appropriate stimulation. A gene called Myo D1, recently isolated from such a myoblast line, will confer myogenesis when expressed in 10T1/2 or other cell types (Davis et al. 1987). The cDNA for Myo D1 contains a large number of CpG sequences and the gene is relatively methylated in 10T1/2 cells and an adipocyte derivative, but is demethylated in myogenic derivatives. Myo D1 may therefore be subject to methylation control in vitro . On the other hand, preliminary observations suggest that Myo D1 is not methylated at CCGG sites in vivo so that a de novo methylation event may have occurred in vitro . These observations may have significance in the establishment of immortal cell lines and tumours.


1985 ◽  
Vol 101 (4) ◽  
pp. 1316-1322 ◽  
Author(s):  
J S Pachter ◽  
R K Liem

In this paper we describe a 66-kD protein that co-purifies with intermediate filaments from rat optic nerve and spinal cord but can be separated further by ion-exchange chromatography. This protein is distinct from the 68-kD neurofilament subunit protein as judged by isoelectric focusing, immunoblotting, peptide mapping, and tests of polymerization competence. This protein is avidly recognized by the monoclonal anti-intermediate filament antigen antibody, previously demonstrated to recognize a common antigenic determinant in all five known classes of intermediate filaments. Also, when isolated this protein binds to various intermediate filament subunit proteins, which suggests an in vivo interaction with the intermediate filament cytoskeleton, and it appears to be axonally transported in the rat optic nerve. Because of this ability to bind to intermediate filaments in situ and in vitro we have named this protein alpha-internexin. A possible functional role for the protein in organizing filament assembly and distribution is discussed.


Science ◽  
1980 ◽  
Vol 208 (4448) ◽  
pp. 1152-1155 ◽  
Author(s):  
RV Zackroff ◽  
RD Goldman

Intermediate filaments from squid brain tissue were reassembled in vitro and purified by two cycles of assembly and disassembly. Purified squid brain filaments contained one major polypeptide (60,000 daltons), which constituted about 70 percent of the total protein, and three minor polypeptides (74,000, 100,000, and 220,000 daltons). Squid brain intermediate filaments were reconstituted from rod-shaped protofilamentous subunits. In addition to the intermediate filaments, dense bodies which may function in intermediate filament nucleation or organization were retained through two purification cycles.


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