TY - JOUR T1 - Olfactory marker protein: turnover and transport in normal and regenerating neurons JF - The Journal of Neuroscience JO - J. Neurosci. SP - 868 LP - 879 DO - 10.1523/JNEUROSCI.04-03-00868.1984 VL - 4 IS - 3 AU - RM Kream AU - FL Margolis Y1 - 1984/03/01 UR - http://www.jneurosci.org/content/4/3/868.abstract N2 - A 19,000-dalton acidic protein designated olfactory marker protein (OMP) is a cell-specific marker of mature olfactory chemosensory neurons. Intranasal irrigation of mouse olfactory epithelium with [35S]methionine labeled OMP to high specific activity. Turnover and transport characteristics of 35S-labeled OMP were compared to those of 35S-labeled global cytosol protein in groups of young, adult, and Triton-treated adult mice. The latter contained primarily large numbers of regenerating olfactory neurons. In olfactory epithelium of young and Triton-treated mice, the specific activity of OMP was three times that of global cytosol protein, whereas in adults the two measures were equal. In all three groups, however, the rate of degradation of OMP was roughly equal to that of cytosol protein (T1/2 = 5 to 6 days). By contrast, differences in T1/2 for OMP decline in the bulb of adult, young, and Triton-treated adult mice were highly significant (T1/2′s of 9.3, 6.1, and 4 to 5 days, respectively; p = 0.001). The specific activity of [35S]methionine incorporated in OMP exceeded that of the free amino acid 5-fold, indicating minimal precursor reutilization during the course of our experiments. Turnover data indicate that increased isotope incorporation into OMP in the epithelium is matched by an accelerated rate of degradation in the bulb. This may be correlated with the physiological state or developmental age of the primary neurons since in young and Triton-treated adult mice, rapidly maturing “young” olfactory neurons represent a larger proportion of the total population than in adults. Thus, OMP behaves as a typical, relatively slowly transported soluble protein (v = 2 to 4 mm/day, slow component b). ER -