pp60c‐src encoded by the proto‐oncogene c‐src is a product of sensory neurons

Publisher Website
Google Scholar
Abstract
The advent of recombinant DNA technology has led to the identification in the DNA of normal animal cells of over 30 proto‐oncogenes that are homologous to retroviral transforming genes. One of these encodes a protein kinase (pp60c‐src) of unknown function, that is preferentially synthesized in brain and neural retina. Here the expression of pp60c‐src in the peripheral nervous system was examined in sensory neurons from chick dorsal root ganglia with antisera raised against the transforming protein of Rous sarcoma virus (pp60c‐src) expressed in Escherichia coli carrying the cloned v‐src gene. This antiserum recognizes pp60c‐src specifically in normal chicken cells. Western immunoblotting showed that dorsal root ganglia of stage 30 (day 6.5) chick embryos contained elevated levels of pp60c‐src. Immunoperoxidase staining of neuron‐enriched cultures prepared from chick dorsal root ganglia showed pp60c‐src immunoreactivity in cells with neuronal morphology; flat, fibroblastic cells contained no detectable immunoreactivity. Indirect double immunofluorescence with pp60c‐src antibodies and monoclonal antibodies against the 200‐kD subunit of neurofilament protein confirmed that the cells expressing pp60c‐src were neurons. Ninety‐six percent of the neurofilament‐positive cells were immunoreactive with pp60c‐src antibodies, and conversely, all pp60c‐src‐positive cells were immunoreactive with neurofilament antibodies. pp60c‐src immunofluorescence appeared to be distributed over the cell body, processes, and growth cones. These results clearly demonstrate that pp60c‐src is a product of neurons and is expressed in sensory neurons in culture.