The epitope recognized by a mouse monoclonal antibody (MAb) to the crystall
ine surface layer protein of Rickettsia typhi, SRT10, was mapped to 10 amin
o acid residues (SRTag TFIGAIATDT). The oligonucleotide sequence covering t
he epitope recognized by SRT10 was inserted into a mammalian expression vec
tor together with multiple cloning sites. When the SRTag was fused in frame
to the coding region of the NCC27/CLIC1 gene and expressed in mammalian ce
lls, the MAb SRT10 could detect the tagged protein by immunoblotting, immun
ocytochemistry, and immunoprecipitation. In addition to the SRT-NCC27/CLIC1
, SRT10 could detect N-terminal-tagged MEF2D and C-terminal-tagged CD4 by i
mmunocytochemistry. We suggest that this specific recognition of the SRTag
by SRT10 is generally applicable to cellular and molecular biology research
that requires the expression and detection of fusion proteins.