In HeLa cells, ribonuclease P (RNase P), the tRNA processing
enzyme consists of an RNA subunit (H1 RNA) associated with at
least nine protein subunits, Rpp14, Rpp20, Rpp21, Rpp29 (hPop4),
Rpp30, Rpp38, Rpp40, hPop1, and hPop5 (18.8 kDa). We report
here the cloning and immuno-biochemical analysis of Rpp25, another
protein subunit of RNase P. Polyclonal rabbit antibodies raised
against recombinant Rpp25 recognize their corresponding antigens
in RNase P-containing fractions purified from HeLa cells, and
they also precipitate active holoenzyme. Furthermore, this protein
has general RNA binding properties.