Journal of Neuroscience, Vol 11, 2453-2459, Copyright © 1991 by Society for Neuroscience
Tau gene expression in rat sensory neurons during development and regeneration
MM Oblinger, A Argasinski, J Wong and KS Kosik
Department of Cell Biology and Anatomy, Chicago Medical School, Illinois 60064.
In the mature rat dorsal root ganglion (DRG), only one tau isoform is
expressed, and this protein (110 kDa in apparent molecular weight) is
considerably larger in size than the predominant tau isoforms found in
brain. The size of the mRNA encoding the "big" tau mRNA in DRG
[approximately 8 kilobases (kb)] is also much larger than that of the major
rat brain tau mRNA species (approximately 6 kb). In this study, we examined
the pattern of normal developmental changes in expression of this
high-molecular-weight (HMW) tau and its encoding mRNA and also determined
how axonal injury of adult DRG neurons effected the expression of this
gene. RNA blotting experiments revealed that higher levels of HMW tau mRNA
were present in the DRG at early postnatal times than in the adult.
Immunoblotting of total DRG protein using a monoclonal tau antibody
revealed that the immature DRG (7 d postnatal) contained a 62-kDa tau
isoform in addition to the HMW tau isoform that was expressed in the adult
DRG. Neither of the tau isoforms expressed in the immature DRG was present
to any significant extent in either immature or adult rat brain. To examine
how tau expression changed in adult DRG neurons during regeneration, the
sciatic nerves of rats were unilaterally crushed, and the L4 and L5 DRG
were harvested 1, 7, and 14 d later.(ABSTRACT TRUNCATED AT 250 WORDS)