Quail neural crest cells transformed by Rous sarcoma virus can be established into differentiating permanent cell cultures

Cell lines derived from mouse neural crest are representative of cells at various stages of differentiation

In order to study mammalian neural crest differentiation in vitro, a series of clonal neural crest (NC) cell lines have been generated by infection of migrating mouse neural crest cells with two recombinant retroviruses containing either the c-myc or N-myc proto-oncogenes. Many cell lines were generated which could be subdivided into three groups based on their appearance in culture. Eleven of these cell lines representative of each of the morphological groups were characterized for the expression of six antigenic markers expressed by neural cells. In addition, mRNA was prepared from these cell lines and analyzed for the expression of a number of neural specific genes. These analyses show that the cell lines are representative of the following cell types: (1) neural crest-like cell lines that do not differentiate in 10% serum; (2) progenitor cell lines, some of which can partially differentiate in culture; and (3) mature neuronal cell lines or bipotential cell lines. Southern blot analysis of DNA from these lines indicated that they have multiple integration sites for the provirus and suggest that phenotypically different cell types have arisen from a single cell. None of the cell lines showed any proliferative or morphological response to nerve growth factor (NGF), whereas over two-thirds of the lines showed both marked proliferative and morphological responses to fibroblast growth factor (FGF). These data indicate that we have generated a range of cell lines representative of a spectrum of mouse neural crest derivatives.

Distinct and different effects of the oncogenes v-myc and v-src on avian sympathetic neurons: retroviral transfer of v-myc stimulates neuronal proliferation whereas v-src transfer enhances neuronal differentiation

Immature avian sympathetic neurons are able to proliferate in culture for a limited number of divisions albeit expressing several neuron-specific properties. The effect of avian retroviral transfer of oncogenes on proliferation and differentiation of sympathetic neurons was investigated. Primary cultures of 6-d-old quail sympathetic ganglia, consisting of 90% neuronal cells, were infected by Myelocytomatosis virus (MC29), which contains the oncogene v-myc, and by the v-src-containing Rous sarcoma virus (RSV). RSV infection, in contrast to findings in other cellular systems, resulted in a reduction of neuronal proliferation as determined by 3H-thymidine incorporation (50% of control 4 d after infection) and in increased morphological differentiation. This is reflected by increased neurite production, cell size, and expression of neurofilament protein. In addition, RSV-infected neurons, unlike uninfected cells, are able to survive in culture for time periods up to 14 d in the absence of added neurotrophic factors. In contrast, retroviral transfer of v-myc stimulated the proliferation of immature sympathetic neurons preserving many properties of uninfected cells. The neuron-specific cell surface antigen Q211 and the adrenergic marker enzyme tyrosine hydroxylase were maintained in MC29-infected cells and in the presence of chick embryo extract the cells could be propagated over several weeks and five passages. Within 7 d after infection, the number of Q211-positive neurons increased approximately 100-fold. These data demonstrate distinct and different effects of v-src and v-myc-containing retroviruses on proliferation and differentiation of sympathetic neurons: v-src transfer results in increased differentiation, whereas v-myc transfer maintains an immature status reflected by proliferation, immature morphology, and complex growth requirements. The possibility of expanding immature neuronal populations by transfer of v-myc will be of considerable importance for the molecular analysis of neuronal proliferation and differentiation.

myc products induce the expression of catecholaminergic traits in quail neural crest-derived cells

The avian myelocytomatosis virus strain MC29 v-myc oncogene transforms a wide panel of avian cells in vitro and either blocks or maintains differentiation, depending on the cell type. In the present work, we have investigated the effect of this oncogene on the differentiation of early embryonic cells, neural crest cells, grown in vitro. We report that the MC29 v-myc gene product induces a strong cellular proliferation of 2-day quail neural crest with the appearance of catecholaminergic traits. Other v-myc as well as the c-myc gene products also trigger this phenotype. Retroviruses carrying some other oncogenes do not elicit this phenotypic expression, although they activate cell multiplication. Thus, our results indicate that myc gene products induce (directly or indirectly) a differentiated phenotype in a subpopulation of neural crest cells.