Proenkephalin A (PEA) gene was found to be expressed in primary, secondary and tertiary cultures of rat fibroblasts. The 1.4 kb PEA mRNA was detected by Northern blot analysis. The same cultures do not express detectable amounts of proenkephalin B (prodynorphin) or (POMC) mRNAs. Acidic cell extracts were purified on a C18 octadecyl Amprep column and analysed with a specific methionine enkephalin radioimmunoassay to detect whether PEA mRNA is translated. A significant amount of enkephalin immunoreactivity (178-185 fmol/mg protein) was observed upon trypsin and carboxypeptidase B digestion of fibroblast cell extracts, whereas only 3-5% of this amount was free enkephalin. It is therefore indicated that the PEA mRNA expressed in fibroblasts is indeed translated to the proenkephalin precursor protein, but the cells accumulate only a small quantity of the processed pentapeptides. The implication of these observations to the possible developmental role of PEA in various non-neuronal cells, including mesodermal lineages, is discussed.
|Original language||American English|
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - 14 Sep 1990|
Bibliographical noteFunding Information:
We thank A. Golm and R. Levy for technical assistance, D. Wilder assistance inpreparingthemanuscript, at-d grant S-UJZ$OI+S( to H.R. R.S., respectively) fm the Fund for Basic Research administeredbythe Israel Academy of Sciences and Humanities, and the Israel Ministry Hfxllth.