Transcripts encoding the 70-75 kDa C-terminal protein product of the dystro
phin gene (Dp71) are alternatively spliced to generate multiple protein pro
ducts in a number of adult human tissues. In this report, reverse transcrip
tase-polymerase chain reaction was used to clone and characterize a subpopu
lation of truncated Dp71 transcripts in adult human brain tissue which did
not contain exons 71-74, resulting in an in-frame deletion of 330 bp encodi
ng the syntrophin-binding domain. These truncated Dp71 transcripts are also
alternatively spliced for exon 78, Immunoblot analysis, using dystrophin-s
pecific C-terminal antibodies directed against epitopes in either exon 77 (
MANDRA1), or 78 (1461), identified full-length dystrophin, Dp140 and Dp71,
in total protein lysates from adult human brain tissue. In addition, a mino
r immunoreactive protein of approximately 58 kDa was also identified (desig
nated Dp71 Delta(110)). The observation that a monoclonal antibody directed
against epitopes within exons 73-74 (MANEX7374A) failed to detect this 58
kDa protein provides definitive evidence that Dp71 Delta(110) is derived fr
om Dp71 transcripts deleted for the syntrophin-binding domain. These result
s, as well as previous findings, demonstrate that alternative splicing of D
p71 in the human brain generates a variety of mRNA transcripts encoding dis
tinct protein variants of Dp71, and further supports the use of exon-specif
ic antibodies in characterizing these variants. The presence of these Dp71
protein variants in brain tissue points to their interaction with various c
ellular proteins and their involvement in different cellular functions. (C)
2000 Elsevier Science B.V. All rights reserved.