Modifications of myelin basic protein in DM20 transgenic mice are similar to those in myelin basic protein from multiple sclerosis.

Abstract

Transgenic mice containing different numbers of transgenes (2-70) of the myelin proteolipid protein DM20 were phenotypically normal up to 3 mo of age, after which the mice containing 70 copies of the transgene spontaneously demyelinated and died at 10-12 mo. Since we demonstrated that demyelination in multiple sclerosis involved specific chemical changes in myelin basic protein (MBP), we investigated the MBP in our transgenic line for similar changes. Both the total amount of MBP in brain and the MBP mRNA levels were unaffected at the different ages. All the isoforms (14-21 kD) of MBP were present, but the microheterogeneity (a posttranslational event) was changed resulting in a higher proportion of the less cationic components reminiscent of the changes in MBP found in multiple sclerosis. An increased amount of the citrullinated form of MBP was found by Western blot analysis. Immunogold labeling of cryosections of brain revealed a greater density of particles with the anticitrulline antibody at 10 mo and that the levels of peptidylarginine deiminase (which deiminates protein-bound arginine to citrulline) were increased. This stable transgenic line represents a useful animal model for the human disease multiple sclerosis. ( J. Clin. Invest. 1996. 97:349-358.)

Increased Citrullination of Histone H3 in Multiple Sclerosis Brain and Animal Models of Demyelination: A Role for Tumor Necrosis Factor-Induced Peptidylarginine Deiminase 4 Translocation

“…ND4 transgenic mice have been described previously (Mastronardi et al, 1993(Mastronardi et al, , 1996Moscarello et al, 2002). They contain 70 copies of the cDNA for the myelin-associated proteolipid protein (PLP) DM20.…”

“…These mice have been described previously (Mastronardi et al, 1993(Mastronardi et al, , 1996Moscarello et al, 2002). They have a normal period of development up to 3 months after birth and thereafter develop a chronic progressive primary CNS demyelination.…”

Loss of myelin basic protein cationicity in DM20 transgenic mice is dosage dependent

“…We expressed the microheterogeneity as a ratio of least cationic to most cationic, i.e., C-8/C-1 (Mastronardi et al, 1996). The microheterogeneity of the ND3A line, heterozygote and homozygote was determined in the same way as we had done with the ND4.…”

“…By 8-10 months these animals are moribund and die shortly thereafter. These mice (ND4) have been characterized extensively both at the morphological (Mastronardi et al, 1993) and the biochemical levels (Mastronardi et al, 1996). Of the biochemical changes observed, changes in myelin basic protein were noteworthy since they correlated with the progress of the demyelinating disease.…”

Deimination of 70-kD Nuclear Protein During Epidermal Apoptotic Events In Vitro

“…Although the loss of the positive charge does not drastically alter the structure of the side chain of the protein, the decreased electrostatic interactions between arginine and other amino acid residues, such as phosphoserine residues, are known to impair the formation of functional secondary structures in several proteins (Imparl et al 1995;Luo et al 1995;Mastronardi et al 1996). The protein-bound arginine residues are known to be converted to citrulline residues by the action of peptidylarginine deiminases (PADs), which belong to the group of Ca 2+ -dependent enzymes (Rothnagel and Rogers 1984).…”