Fig. 4.

Cell type-specific expression ofperipherin in lower motor neurons requires intron 1. Cross sections of adult mouse cervical spinal cord were double labeled with a polyclonal myc antibody (A, C) and a monoclonal peripherin antibody (B, D) to determine the degree of overlap between transgenic and endogenous protein. In the intron-1 containing Periph/Δi2–8-myctransgenic mice (A, B, white arrows), transgene expression mimics that of endogenousperipherin, but in most of thePeriph/intronless transgenic mice, the only evidence of transgene expression in the lower motor neurons (C,D, white arrowheads) was an occasional labeled fiber in the ventral root (C,D, open arrows). Scale bar, 20 μm.