title: Disproportional expression of proteolipid protein and DM-20 in the X-linked, dysmyelinating shaking pup mutant.
abstract: The shaking pup is an X-linked canine mutant with a severe hypomyelination of the CNS. Proteolipid protein (PLP) and the related DM-20 protein were examined in this mutant by densitometric scanning of Western blots stained with PLP antiserum. In the spinal cord of 4-week-old mutants, PLP was reduced to less than 1% of the control level, which is a greater deficiency than was found for other myelin proteins. On Western blots of control spinal cord, PLP stained much more intensely than DM-20. However, on Western blots of the mutant spinal cord, a component with the electrophoretic mobility of DM-20 stained slightly more intensely with PLP antiserum than PLP itself. This component was shown to be DM-20 by its lack of reactivity with an antiserum raised to a synthetic peptide corresponding to part of the PLP sequence that is missing in DM-20. Thus PLP and DM-20 are expressed in approximately equal and greatly reduced amounts in the mutant spinal cord. Although PLP or DM-20 could not be detected in brain from the 4-week-old mutant, similar disproportional expression of these two proteins was demonstrated in both spinal cord and brain from a 10-week-old mutant pup. Immunostaining of tissue sections showed that the small amounts of PLP and/or DM-20 synthesized in the mutant are present in the thin myelin sheaths. The results suggest that the shaking pup could have a primary defect in the PLP gene leading to a severe deficiency of PLP and DM-20 as well as disproportional expression of these two proteins.
mesh_terms: D000818:Animals; D003711:Demyelinating Diseases / Q000235:genetics*; D004285:Dogs; D005786:Gene Expression Regulation; D007118:Immunoassay; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D009185:Myelin Proteins / Q000172:deficiency / Q000235:genetics*; D018991:Myelin Proteolipid Protein; D009186:Myelin Sheath / Q000378:metabolism; D011510:Proteolipids / Q000172:deficiency / Q000235:genetics*; D013116:Spinal Cord / Q000378:metabolism; D014960:X Chromosome
chemical_list: D009185:Myelin Proteins; D018991:Myelin Proteolipid Protein; D011510:Proteolipids