Cloning and expression of the proteolipid protein DM20 cDNA from the brain of the rainbow trout, Oncorhynchus mykiss.
The myelin sheath in higher vertebrates consists predominantly of proteolipid protein (PLP) and its smaller isoform DM20. Mutations in the PLP gene produces several neurological disorders such as Pelizaeus-Merzbacher disease and the rumpshaker phenotype in mice. This paper describes the cloning and expression of DM20 from the brain of Rainbow trout. We have isolated a nearly full-length cDNA clone containing 1835 bp that codes for a protein of 258 amino acids. Trout DM20 shows extensive homology with DM20 from higher vertebrates and includes the four hydrophobic regions that are believed to span the myelin membrane. The DM20 transcript is expressed throughout the central nervous system of the trout but appears at its highest levels in the spinal cord and medulla oblongata. The transcript is expressed at very low levels on hatching day but increases 179-fold by the 5th week. Contrary to higher vertebrates, there is no switch to the PLP transcript in maturing trout. Moreover, the rsh mutation (186 Thr to Ile) that produces the rumpshaking neurological disorder in mice has no effect in trout.
Tang
S
S
Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada.
Panno
J P
JP
McKeown
B A
BA
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000196:embryology / Q000254:growth & development; D001923:Brain Chemistry; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D029941:Fish Proteins; D018507:Gene Expression Regulation, Developmental; D015723:Gene Library; D006801:Humans; D051379:Mice; D008818:Mice, Neurologic Mutants; D008969:Molecular Sequence Data; D018991:Myelin Proteolipid Protein / Q000096:biosynthesis / Q000235:genetics*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics*; D017686:Oncorhynchus mykiss / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D009928:Organ Specificity; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics* / Q000302:isolation & purification; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
D018076:DNA, Complementary; D029941:Fish Proteins; D018991:Myelin Proteolipid Protein; D009419:Nerve Tissue Proteins; C489072:PLP protein, Oncorhynchus mykiss; C047516:Plp1 protein, mouse; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins