Quantitative differences between homozygous 'USA' and 'Swiss' mld mutant mice.
Parallel developmental studies of central nervous system myelin proteins and morphology (postnatal days 15-118; P15-118) confirm qualitative similarities but substantial quantitative differences between homozygous mld mice with Billings-Gagliardi and Wolf's 'USA' versus Matthieu's 'Swiss' genetic backgrounds. The USA mld/mld have fewer convulsions and significantly longer life span. While whole-brain homogenates from both Swiss and USA mld/mld show increases in myelin basic protein (MBP) and in 2',3'-cyclic nucleotide 3'-phosphohydrolase specific activity with age, at P50 and older the levels of both proteins are approximately twice as high in the Swiss. The number of optic nerve axons myelinated is always greater in Swiss mld/mld, and they have approximately twice as many myelin sheaths showing any apposition of cytoplasmic membrane faces (the location of the major dense line in normal myelin), except at the youngest age. Evidence is presented which suggests that these quantitative differences between Swiss and USA mld stocks most likely reflect different regulatory genes influencing the expression of the same (mld) allele, rather than the presence of a different allele at the MBP locus.
Billings-Gagliardi
S
S
Department of Cell Biology, University of Massachusetts Medical School, Worcester.
Tosic
M
M
Matthieu
J M
JM
Kirschner
D A
DA
Wolf
M K
MK
D000375:Aging / Q000502:physiology; D000818:Animals; D015139:Blotting, Southern; D004247:DNA / Q000032:analysis; D005298:Fertility / Q000502:physiology; D051379:Mice; D008809:Mice, Inbred C3H; D008813:Mice, Inbred ICR; D008818:Mice, Neurologic Mutants / Q000502:physiology*; D004676:Myelin Basic Protein / Q000032:analysis / Q000235:genetics*; D009186:Myelin Sheath / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000502:physiology; D009693:Nucleic Acid Hybridization; D009836:Oligodendroglia / Q000502:physiology; D009900:Optic Nerve / Q000166:cytology / Q000502:physiology; D013045:Species Specificity
D004676:Myelin Basic Protein; D009419:Nerve Tissue Proteins; D004247:DNA