Differential developmental expression of cellular yes and cellular src proteins in cerebellum.

To identify the specific areas of the brain that express c-yes and c-src proteins, we examined chicken brains dissected from two-week-old birds using an immune complex kinase assay and an immune blot analysis. Highest levels of both proto-oncogene proteins were found in the cerebellum, whereas other parts of the brain, including telencephalon, diencephalon, mesencephalon and spinal cord, showed three- to six-times lower levels. Relatively low levels of the two proteins were detected in pineal body and pituitary.

Monoclonal antibody reveals radial glia in adult avian brain.

An antibody prepared against adult canary brain, 40E-C, stains ventricular zone cells that send long, unbranched processes into the forebrain parenchyma. We identify these cells as radial glia. The same antibody also stains a subset of brain astroglia and reacts with nonbrain material such as mesenchyme, Sertoli cells, and the Z-line of muscle.

Mouse primordial germ cells use fibronectin as a substrate for migration.

The behavior in vitro of mouse primordial germ cells (PGCs) on different substrates was studied by means of microcinematography. It was observed that for displacement, the PGCs required fibronectin in the substrate and that this glycoprotein was present in vivo in those routes along which the cells moved. It was concluded that fibronectin plays an important role in the migration of the PGCs to the genital crests.

Production of plasminogen activator in cultures of superior cervical ganglia and isolated Schwann cells.

Plasminogen activator has been implicated in tissue remodeling and cell migration during embryogenesis. In the developing nervous system, these processes are evident in the migration of neurons, axonal extension, Schwann cell migration, and the ensheathment and myelination of nerves. We have studied the production of plasminogen activator in cultures of superior cervical ganglia under conditions in which both neurons and glia are present.

Characterization of alkaline phosphatase from primordial germ cells and ontogenesis of this enzyme in the mouse.

The physical characteristics of nonspecific alkaline phosphatase (ALP) from both mouse primordial germ cells (PGCs) and gonads were compared with corresponding samples from other organs at different developmental stages. Combining a cytochemical approach with polyacrylamide gel electrophoresis and the use of specific inhibitors, as well as neuraminidase treatment, heat sensitivity tests, and molecular-mass criteria, it was found that only one ALP isoenzyme was present in all organs up to day 14 of gestation. Distinct ALP isoenzymes first appeared in the small intestine on day 15 and, thereafter, in all other tissues except the gonads.