Journal article
Characterization of Multiple Isoforms of Protein 4.1R Expressed During Erythroid Terminal Differentiation
Blood, Vol.92(11), pp.4404-4414
12/01/1998
DOI: 10.1182/blood.V92.11.4404
Abstract
Abstract In erythrocytes, 80-kD protein 4.1R regulates critical membrane properties of deformability and mechanical strength. However, previously obtained data suggest that multiple isoforms of protein 4.1, generated by alternative pre-mRNA splicing, are expressed during erythroid differentiation. Erythroid precursors use two splice acceptor sites at the 5′ end of exon 2, thereby generating two populations of 4.1 RNA: one that includes an upstream AUG-1 in exon 2′ and encodes high molecular weight isoforms, and another that skips AUG-1 in exon 2′ and encodes 4.1 by initiation at a downstream AUG-2 in exon 4. To begin an analysis of the complex picture of protein 4.1R expression and function during erythropoiesis, we determined the number and primary structure of 4.1R isoforms expressed in erythroblasts. We used reverse-transcription polymerase chain reaction to amplify and clone full-length coding domains from the population of 4.1R cDNA containing AUG-1 and the population excluding AUG-1. We observed an impressive repertoire of 4.1R isoforms that included 7 major and 11 minor splice variants, thus providing the first definitive characterization of 4.1R primary structures in a single-cell lineage. 4.1R isoforms, transfected into COS-7 cells, distributed to the nucleus, cytoplasm, plasma membrane, and apparent centrosome. We confirmed previous studies showing that inclusion of exon 16 was essential for efficient nuclear localization. Unexpectedly, immunochemical analysis of COS-7 cells transfected with an isoform lacking both AUG-1 and AUG-2 documented that a previously unidentified downstream translation initiation codon located in exon 8 can regulate expression of 4.1R. We speculate that the repertoire of primary structure of 4.1R dictates its distinct binding partners and functions during erythropoiesis.
Details
- Title: Subtitle
- Characterization of Multiple Isoforms of Protein 4.1R Expressed During Erythroid Terminal Differentiation
- Creators
- P Gascard - From the Life Science Division, Biophysics and Biomolecular Structure Department, Lawrence Berkeley National Laboratory, Berkeley, CA; and the Laboratoire Hématopoı̈èse et Cellules Souches, Villejuif, FranceG Lee - From the Life Science Division, Biophysics and Biomolecular Structure Department, Lawrence Berkeley National Laboratory, Berkeley, CA; and the Laboratoire Hématopoı̈èse et Cellules Souches, Villejuif, FranceL Coulombel - From the Life Science Division, Biophysics and Biomolecular Structure Department, Lawrence Berkeley National Laboratory, Berkeley, CA; and the Laboratoire Hématopoı̈èse et Cellules Souches, Villejuif, FranceI Auffray - From the Life Science Division, Biophysics and Biomolecular Structure Department, Lawrence Berkeley National Laboratory, Berkeley, CA; and the Laboratoire Hématopoı̈èse et Cellules Souches, Villejuif, FranceM Lum - From the Life Science Division, Biophysics and Biomolecular Structure Department, Lawrence Berkeley National Laboratory, Berkeley, CA; and the Laboratoire Hématopoı̈èse et Cellules Souches, Villejuif, FranceM Parra - From the Life Science Division, Biophysics and Biomolecular Structure Department, Lawrence Berkeley National Laboratory, Berkeley, CA; and the Laboratoire Hématopoı̈èse et Cellules Souches, Villejuif, FranceJ.G Conboy - From the Life Science Division, Biophysics and Biomolecular Structure Department, Lawrence Berkeley National Laboratory, Berkeley, CA; and the Laboratoire Hématopoı̈èse et Cellules Souches, Villejuif, FranceN Mohandas - From the Life Science Division, Biophysics and Biomolecular Structure Department, Lawrence Berkeley National Laboratory, Berkeley, CA; and the Laboratoire Hématopoı̈èse et Cellules Souches, Villejuif, FranceJ.A Chasis - From the Life Science Division, Biophysics and Biomolecular Structure Department, Lawrence Berkeley National Laboratory, Berkeley, CA; and the Laboratoire Hématopoı̈èse et Cellules Souches, Villejuif, France
- Resource Type
- Journal article
- Publication Details
- Blood, Vol.92(11), pp.4404-4414
- DOI
- 10.1182/blood.V92.11.4404
- ISSN
- 0006-4971
- eISSN
- 1528-0020
- Language
- English
- Date published
- 12/01/1998
- Academic Unit
- Immunology; Internal Medicine; Iowa Neuroscience Institute
- Record Identifier
- 9984070727302771
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