The mouse filensin gene: structure and evolutionary relation to other intermediate filament genes.
Filensin and phakinin are two lens-specific members of the intermediate filament (IF) superfamily of proteins. They coassemble to form a beaded submembraneous filamentous network, the beaded filaments (BFs). The low sequence homology and differences in assembly compared to other IF proteins do not allow their classification in any of the five IF subgroups. The organization of the phakinin gene exon/intron boundaries provides evidence that this partner may be sharing a common origin with type I cytokeratin genes. Here we report the molecular cloning, sequence and characterization of the mouse filensin gene. The filensin gene consists of 8 exons and 7 introns, with 6 introns interrupting its rod domain in a highly conserved manner characteristic of type III IF genes, like vimentin, desmin, or peripherin. Of the two tail domain exons the one adjacent to the rod domain, compares to exon 7 of the non-neuronal cytoplasmic IF gene of helix aspersa and to the lamin region bridging the end of the rod domain to the nuclear localization signal. Altogether, these observations indicate that the lens beaded filaments form an independent class of IF.
Gounari
F
F
Abteilung 710, Schwerpunkt Tumorimmunologie, Deutsches Krebsforschungzentrum, Heidelberg, Germany. f.gounari@dkfz-heidelberg.de
Karagianni
N
N
Mincheva
A
A
Lichter
P
P
Georgatos
S D
SD
Schirrmacher
V
V
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000235:genetics; D019143:Evolution, Molecular; D005091:Exons / Q000235:genetics; D005136:Eye Proteins / Q000235:genetics*; D005260:Female; D018628:Gene Dosage; D005796:Genes / Q000235:genetics*; D007381:Intermediate Filament Proteins / Q000235:genetics*; D007438:Introns / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D005136:Eye Proteins; D007381:Intermediate Filament Proteins; C079098:filensin