title: Alternative mRNA splicing from the glial fibrillary acidic protein (GFAP) gene generates isoforms with distinct subcellular mRNA localization patterns in astrocytes.
abstract: The intermediate filament network of astrocytes includes Glial fibrillary acidic protein (Gfap) as a major component. Gfap mRNA is alternatively spliced resulting in generation of different protein isoforms where Gfapα is the most predominant isoform. The Gfapδ isoform is expressed in proliferating neurogenic astrocytes of the developing human brain and in the adult human and mouse brain. Here we provide a characterization of mouse Gfapδ mRNA and Gfapδ protein. RT-qPCR analysis showed that Gfapδ mRNA and Gfapα mRNA expression is coordinately increased in the post-natal period. Immunohistochemical staining of developing mouse brain samples showed that Gfapδ is expressed in the sub-ventricular zones in accordance with the described localization in the developing and adult human brain. Immunofluorescence analysis verified incorporation of Gfapδ into the Gfap intermediate filament network and overlap in Gfapδ and Gfapα subcellular localization. Subcellular mRNA localization studies identified different localization patterns of Gfapδ and Gfapα mRNA in mouse primary astrocytes. A larger fraction of Gfapα mRNA showed mRNA localization to astrocyte protrusions compared to Gfapδ mRNA. The differential mRNA localization patterns were dependent on the different 3'-exon sequences included in Gfapδ and Gfapα mRNA. The presented results show that alternative Gfap mRNA splicing results in isoform-specific mRNA localization patterns with resulting different local mRNA concentration ratios which have potential to participate in subcellular region-specific intermediate filament dynamics during brain development, maintenance and in disease.
authors.affiliation: Department of Biomedicine, Aarhus University, Aarhus, Denmark.
authors.forename: Rune
authors.initials: R
authors.lastname: Thomsen
authors.forename: Tina F
authors.initials: TF
authors.lastname: Daugaard
authors.forename: Ida E
authors.initials: IE
authors.lastname: Holm
authors.forename: Anders Lade
authors.initials: AL
authors.lastname: Nielsen
mesh_terms: D000328:Adult; D017398:Alternative Splicing; D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001483:Base Sequence; D001921:Brain / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005904:Glial Fibrillary Acidic Protein / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D051379:Mice; D018345:Mice, Knockout; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid
chemical_list: D005904:Glial Fibrillary Acidic Protein; D020033:Protein Isoforms; D012333:RNA, Messenger