Ras protein expression is developmentally regulated in embryonic chicken brain.

Immunoblot analysis using a panreactive monoclonal antibody directed against ras p21 proteins detects two differentially regulated ras pools in embryonic chicken brain: a membrane pool that is not changed and a microsomal pool that starts at a low level but is strongly increased from E6 to E16 chicken brain. In order to study the distribution of ras proteins in different cell types of the nervous system, immunoblot analysis was performed on total cell proteins. In contrast to histochemical data showing the absence or low levels of ras proteins in glial cells, comparable amounts of ras proteins were found in cell lysates from purified chicken sympathetic neurons, cultured rat Schwann cells and mouse brain astrocytes.