EVOLUTION OF THE MAMMALIAN G-PROTEIN ALPHA-SUBUNIT MULTIGENE FAMILY

Heterotrimeric guanine nucleotide binding proteins (G proteins) transduce extracellular signals received by transmembrane receptors to effector proteins. The multigene family of G protein alpha-subunits, which interact with receptors and effectors, exhibit a high level of sequence diversity. In mammals, 15 G-alpha subunit genes can be grouped by sequence and functional similarities into four classes. We have determined the murine chromosomal locations of all 15 G-alpha subunit genes using an interspecific backcross derived from crosses of C57BL/6J and Mus spretus mice. These data, in combination with mapping studies in humans, have provided insight into the events responsible for generating the genetic diversity found in the mammalian alpha-subunit genes and a framework for elucidating the role of the G-alpha subunits in disease.