Structure of the mouse glial fibrillary acidic protein gene: implications for the evolution of the intermediate filament multigene family

Abstract

We report the complete sequence of the gene encoding mouse glial fibrillary acidic protein (GFAP), the intermediate filament (IF) protein specific to astrocytes. The 9.8 kb gene includes nine exons separated by introns ranging 1n size from 0.2 to 2.5 kb. A comparison of the organization of the GFAP gene with that of genes encoding other IF proteins reveals that the structure of IF genes Is highly conserved in spite of considerable divergence at the amino add level. Thus, most of the evolutionary events leading to the placement of introns 1n IF genes must have occurred prior to the duplication and subsequent divergence of IF genes from a presumptive common ancestral sequence. The conserved gene organization is unrelated to structural features of IFproteins.