| First Author | Tsao JW | Year | 1993 |
| Journal | J Neurochem | Volume | 61 |
| Issue | Suppl | Pages | S111 (Abstr) |
| Mgi Jnum | J:13191 | Mgi Id | MGI:61397 |
| Citation | Tsao JW, et al. (1993) The mouse C57BL/Wld mutation results in a slower degradation of neurofilaments but does not affect their proteolyis in vitro. J Neurochem 61(Suppl):S111 (Abstr) |
| abstractText | Full text of Abstract: A. THE MOUSE C57BL/Wld MUTATION RESULTS IN A SLOWER DEGRADATION OF NEUROFILAMENTS BUT DOES NOT AFFECT THEIR PROTEOLYSIS IN VITRO. J.W. Tsao*|, M.C. Brown*|, M.J. Carden*&, W.G. McLean + and V.H. Perry*++, Departments of ++Pharmacology and |Physiology, University of Oxford, +Department of Pharmacology, University of Liverpool and &Biological Laboratory, University of Kent, U.K. In the CS7BL/Wld mouse strain, a single gene mutation controls the marked slowing of axonal disintegration following a nerve transection. The protective effect of this mutation decreases with aging. We have studied neurofilament stability and phosphorylation in sciatic nerves of Wld mice and their relationship to changes in nerve electrophysiology. The left sciatic nerve of C57BL/Wld, C57BL/6J and Balb/c mice aged 1, 6 or 12 months was transected under surgical anaesthesia. Between 1 and 21 days later, transected and contralateral (control) nerves were removed or, in some cases, isolated sciatic nerves were incubated in culture medium in vitro for 1-14 days, and the size of the compound action potential (CAP) was measured. The activity of intrinsic Ca++ dependent proteases was measured by incubating nerve homogenates for 2-18 h in 10mM CaCl2. To assay for the presence of neurofilament proteins NF-H and NF-M, nerve pieces were subjected lo SDS-polyacrylamide gel electrophoresis and Western blots of separated proteins were probed with monoclonal antibodies Ta51, RMd09, RM044and RM055 against phosphorylated and non- phosphorylated epitopes of NF-11 and NF-M. In all mice studied, the presence of a CAP was detectable only when subsequent analyses indicated the presence of NF-H and normal axonal architecture. In 1 month-old Wld mice, NF-H and NF-M could still be detected 21 days after transection, whereas NF-H was undetectable and only a trace of NF-M remained by 2 days in Balb/c and 6J mice of the same age. In contrast, NF-H was barely detectable in 12 month-old Wld mice as early as 7 days after transection. The rates of degenerntien were more rapid in vitro than in vivo in Wld mice, but similar in Balb/c and 6J animals. Proteolytic digestion of neuro- filaments in vitro in the presence of Ca++ was similar in Wld and Balb/c mice and there was no evidence of a difference in NF-H or NF-M phosphorylation. Supported by the Wellcome Trust, Bristol Myers Squibb, U.K. and Howard Hughes Medical Institute, U.S.A. |
