Early upregulation of medium neurofilament gene expression in developing spinal cord of the wobbler mouse mutant.
Homozygous wobbler mouse mutants develop a progressive paralysis due to spinal motoneuron degeneration. To understand the molecular aspect underlying the genetic defect we have studied the embryonic (from E13) and postnatal expression of the three neurofilament and choline acetyltransferase genes in each member from several wild-type (wt) and wobbler (wr) progenies. There are no variations among wt littermates at all ages studied. In contrast, analyses of neurofilament mRNA reveals a 3-4-fold increase of medium neurofilament (NFM) mRNA in wobbler mice (wr/wr). The pattern of increased NFM mRNA during development, prior to the appearance of the wobbler phenotype, among littermates (from heterozygous carriers) conforms to a mendelian inheritance of a single gene defect 1:2:1 (wr/wr:wr/+:+/+). Light and heavy neurofilament mRNA levels are also increased later in development exclusively in those individuals with high NFM mRNA values indicating that increase of the latter is associated with increase of the light and heavy subunit expression. Also NF proteins are increased. Expression of choline acetyltransferase gene is instead always comparable to normal control. Our study provides novel insights into the nature of the wobbler defect, strengthening the hypothesis that neurofilament accumulation plays a pivotal role in the etiopathogenesis of motoneuron degeneration.
Pernas-Alonso
R
R
International Institute of Genetics and Biophysics, C.N.R., Naples, Italy.
Schaffner
A E
AE
Perrone-Capano
C
C
Orlando
A
A
Morelli
F
F
Hansen
C T
CT
Barker
J L
JL
Esposito
B
B
Cacucci
F
F
di Porzio
U
U
D000818:Animals; D002795:Choline O-Acetyltransferase / Q000235:genetics*; D005314:Embryonic and Fetal Development / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D005808:Genes, Recessive; D006580:Genetic Carrier Screening; D006720:Homozygote; D051379:Mice; D008818:Mice, Neurologic Mutants; D009046:Motor Neurons / Q000502:physiology; D009134:Muscular Atrophy, Spinal / Q000235:genetics*; D009410:Nerve Degeneration; D016900:Neurofilament Proteins / Q000235:genetics*; D013116:Spinal Cord / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D015854:Up-Regulation
D016900:Neurofilament Proteins; D002795:Choline O-Acetyltransferase