Enhancing factor, a Paneth cell specific protein from mouse small intestines: predicted amino acid sequence from RT-PCR amplified cDNA and its expression.

Enhancing factor (EF), a Paneth cell specific growth factor modulator, has been identified in our laboratory from mouse small intestines. In this paper we describe generation of an EF specific cDNA by RT-PCR and its sequence. The predicted amino acid sequence was found to be similar to, and hence confirms, the partial amino acid sequence obtained earlier by protein sequencing. In Northern blot analysis, a 1 kb transcript was observed in intestinal RNA alone. In situ hybridization indicated that the EF gene is expressed exclusively in the Paneth cells. The present study indicates that EF is an isoform of PLA2 type II, with a unique tissue distribution, found predominantly in the Paneth cells of the small intestines. Further, based on the properties of EF, we propose that isoforms of PLA2, belonging to type II, may be involved in regulation of cell proliferation via EGF binding.