Sequence and expression of a glyceraldehyde-3-phosphate dehydrogenase-encoding gene from quail embryo fibroblasts

Using differential hybridization techniques, a cDNA library derived from a line of v-myc-transformed quail embryo fibroblasts was screened for clones whose expression was elevated in transformed, as compared with normal, cells. One of the isolated clones contained the entire coding region of the quail glyceraldehyde-3-phosphate dehydrogenase-encoding gene (GAPDH). A comparison of the deduced 333-amino-acid (aa) sequence of quail GAPDH with that of the only other avian (chicken) GAPDH sequence known, and with those of mammalian counterparts indicates the strong aa sequence conservation of this glycolytic enzyme. GAPDH is expressed in all transformed and non-transformed quail and chicken embryo fibroblasts and macrophages tested, with a moderate elevation of expression in most of the transformed cell lines. In the avian genomes, GAPDH is present in a single copy, in contrast to the high number of GAPDH-related sequences in mammalian species.