We previously reported that expression of myotonic dystrophy (DM1) expanded CUG repeats impedes NGF-induced differentiation in a PC12 clone (CTG90 cells). Here, we present evidence for changes in the fractional contribution of distinct voltage-gated Ca 2+ channels, key elements in neurotrophin-promoted differentiation, to the total Ca 2+ current in the CTG90 cells. Patch-clamp recordings showed that the relative proportion of pharmacologically isolated Ca 2+ channel types differed between control and CTG90 cells. Particularly, the functional expression of N-type channels was significantly reduced. Though quantitative real-time RT-PCR revealed that transcripts for the pore-forming subunit encoding the N-type channels remained unchanged, the protein level analyzed by semi-quantitative Western blotting was down-regulated in the CTG90 cells. These data suggest modifications in the processing of N-type Ca 2+ channels in PC12 cells expressing the DM1 mutation.
Bibliographical noteFunding Information:
This work was supported by Grants from Conacyt to R.F., and from the Muscular Dystrophy Association (MDA-3693) to B.C. Doctoral and postdoctoral fellowships from Conacyt to A.A. and O.H.H, respectively, are gratefully acknowledged. We also thank Victor Tapia for assistance with cell cultures, and Dr. Manuel Hernandez (Cinvestav-IPN, Mexico) for his generous gift of the β-actin antibodies.
Copyright 2008 Elsevier B.V., All rights reserved.
All Science Journal Classification (ASJC) codes
- Structural Biology
- Molecular Biology
- Cell Biology