Synemin expression in brain.

beta-Synemin has been identified as an alpha-dystrobrevin-interacting protein in human muscle, although at least two synemin transcripts are expressed in brain. To understand synemin's function in neural tissue, in situ and immunohistochemical analyses were performed to identify where alpha- and beta-synemin are expressed in the brain of C57BL/6 and mdx (dystrophin null) mice. This analysis shows that the alpha- and beta-synemin transcripts and their encoded proteins colocalize in neurons, especially in the midbrain and pons. Since alpha-dystrobrevin-1 and synemin do not colocalize in brain as in muscle, this suggests that another member of the dystrophin-associated protein complex might interact with synemin in brain. In support of this, synemin mRNA expression was decreased in mdx mice, suggesting that synemin transcription is linked to dystrophin expression. Our findings show where synemin is expressed in brain and allow one to speculate with regard to its function in neural tissue.