Characterisation of neurofilament protein NF70 mRNA from the gastropod Helix aspersa reveals that neuronal and non-neuronal intermediate filament proteins of cerebral ganglia arise from separate lamin-related genes.
The neuronal cytoplasmic intermediate filament (IF) protein HeNF70 of the gastropod Helix aspersa is identified by sequence analysis of the corresponding 4,600 bp cDNA isolated from a cerebral ganglion cDNA library. HeNF70 shares 60% sequence identity with the neuronal LoNF70 protein of the cephalopod Loligo pealei and only 36% identity with the Helix non-neuronal IF-A protein. All three molluscan IF proteins display the lamin-type extended coil 1b subdomain harbouring six additional heptads and all have long C-terminal sequences with substantial homology to the tail domains of nuclear lamins. The lamin-like tail domains of the two neurofilament proteins share a unique motif comprising 13 residues, which is absent from Helix IF-A and all other known non-neuronal IF proteins. HeNF70 is encoded by a 9.5 kb RNA transcript. The very long 7.2 kb 3'-untranslated sequence contains a unique 26 nucleotide repeat extending over 0.5 kb in its 5'-region. The HeNF70 mRNA is expressed at low abundancy in cerebral ganglia but not in any of the 13 non-neuronal tissues tested. In contrast, all tissues express at fairly high levels the same 4.6 and 4.2 kb mRNAs encoding the Helix non-neuronal IF-A/B proteins. Blot hybridisation studies on genomic DNA and ganglion mRNA with subprobes from the cloned HeNF70 cDNA, as well as sequence analysis of an RT-PCR generated partial cDNA encoding a putative HeNF60 protein, indicate at least two different neuronal IF genes in Helix.
Adjaye
J
J
Max Planck Institute for Biophysical Chemistry, Department of Biochemistry, Goettingen, Germany.
Plessmann
U
U
Weber
K
K
Dodemont
H
H
D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary / Q000032:analysis; D017952:Ganglia, Invertebrate / Q000502:physiology; D006372:Helix, Snails / Q000235:genetics*; D007382:Intermediate Filaments / Q000235:genetics*; D034882:Lamins; D008969:Molecular Sequence Data; D016900:Neurofilament Proteins / Q000235:genetics* / Q000648:ultrastructure; D009687:Nuclear Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic / Q000502:physiology
D018076:DNA, Complementary; D034882:Lamins; C098235:NF70 protein, Helix aspersa; D016900:Neurofilament Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger