Structure of an invertebrate gene encoding cytoplasmic intermediate filament (IF) proteins: implications for the origin and the diversification of IF proteins.

摘要: The structure of the single gene encoding cytoplasmic intermediate filament (IF) proteins in non-neuronal cells gastropod Helix aspersa is described. Genomic and cDNA sequences show that composed 10 introns 11 exons, spanning greater than 60 kb DNA. Alternative RNA processing accounts for two mRNA families which encode IF differing only their C-terminal sequence. intron/exon organization rod domain identical to vertebrate type III genes spite low overall protein sequence homology presence an additional 42 residues coil 1b invertebrate Intron position extends entire coding comprising both tail domains when compared with nuclear lamin LIII Xenopus laevis presented accompanying report Doring Stick. In contrast intron patterns differ from those genes. combined data are line evolutionary descent a lamin-like progenitor suggest mechanism this derivation. unique 7 indicates archetype arose by elimination localization due recruitment novel splice site. presumptive structural allows predictions respect later diversification metazoan Whereas models proposing direct derivation neurofilament seem unlikely, earlier speculation transposition compatible current results.