FUNCTIONAL EQUIVALENCE AND RESCUE AMONG GROUP-11 HOX GENE-PRODUCTS INVERTEBRAL PATTERNING

Hoxa-11 and Hoxd-11 are paralogous genes required for proper developme nt of the vertebral column, the limbs, and the urogenital system, To f urther explore the functional relationship between these genes, as wel l as the potential rescue of one function by the other, we have introd uced a Hoxd-11-expressing transgene into Hoxa-11/Hoxd-11 mutant geneti c backgrounds. A range of phenotypes was observed, with transgenic mic e displaying as few as four lumbar vertebrae while double mutant mice had as many as eight. When transgenic, double homozygote mutant animal s showed six lumbar vertebrae, instead of the eight usually observed. The phenotypic rescue of these genotypes shows that the Hoxa-11 and Ho xd-11 products are functionally equivalent and that extra doses of Hox d-11 can rescue Hoxa-11 loss of function. (C) 1996 Academic Press, Inc .