A high-molecular-weight squid neurofilament protein contains a lamin-like rod domain and a tail domain with Lys-Ser-Pro repeats.
Previous studies have shown that two low molecular-weight neurofilament (NF) proteins (NF-60 and NF-70) from the squid Loligo pealei are translated from mRNAs that are splice variants of a single squid NF gene. In this study, we report the isolation and characterization of cDNA clones encoding a high-molecular-weight squid NF protein (NF-220), the mRNA of which derives from the same squid NF gene. All three proteins are identical in their amino-terminal and lamin-like rod domains but differ in their carboxyl-terminal tail regions. In contrast to the short tail domains of NF-60 and NF-70, the NF-220 protein has a longer tail domain containing an acidic cluster of amino acids immediately followed by repeated copies of the sequence motif Lys-Ser-Pro. The Lys-Ser-Pro domain is similar to that of mammalian medium NF (NF-M) and high NF (NF-H) proteins, where the serines are highly phosphorylated. Except for these Lys-Ser-Pro motifs, there is surprisingly little structural similarity between the squid NF-220 protein and mammalian NF-M and NF-H proteins. Furthermore, the location of introns in squid NF-220 protein shows that it is more closely related to nuclear lamins and type III intermediate-filament proteins than to vertebrate NF proteins.
Way
J
J
Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.
Hellmich
M R
MR
Jaffe
H
H
Szaro
B
B
Pant
H C
HC
Gainer
H
H
Battey
J
J
D000595:Amino Acid Sequence; D000818:Animals; D004247:DNA / Q000235:genetics*; D049832:Decapodiformes / Q000235:genetics*; D015698:Genomic Library; D006801:Humans; D007438:Introns; D034882:Lamins; D008322:Mammals; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009132:Muscles / Q000502:physiology; D009424:Nervous System Physiological Phenomena; D016900:Neurofilament Proteins / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics*; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid; D013233:Stellate Ganglion / Q000502:physiology
D034882:Lamins; D016900:Neurofilament Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D012313:RNA; D004247:DNA