[(Proto)-oncogenes, cellular growth and development].

Abstract

In the past few years, one realizes that number of genes whose products are involved in regulating normal cell growth and development are also capable of inducing malignancy. These genes are called oncogenes and include 1 degree the cellular oncogenes (c-onc) or proto-oncogenes and 2 degrees the viral oncogenes (v-onc) which are most likely derived from c-onc and which are the transforming genes of several strains of animal retrovirus. The c-onc are present in the genome of all vertebrate cells and show a remarkable degree of evolutionary conservation, suggesting that they serve essential cellular functions. The analysis of biological properties of both types of oncogenes is of importance to understand the role of proto-oncogenes in normal cell proliferation and/or differentiation and development and to determine how alterations in their structures play a role in malignant transformation. In order to give an overview of the diversity of oncogene activities, several oncogene products involved in growth control, signal transduction, gene expression and development will be described.