HOXC13 MUTANT MICE LACK EXTERNAL HAIR

Hox genes are usually expressed temporally and spatially in a colinear manner with respect to their positions in the Hox complex. Consistent with the expected pattern for a paralogous group 13 member, early emb ryonic Hoxc13 expression is found in the nails and tail. Hoxc13 is als o expressed in vibrissae, in the filiform papillae of the tongue, and in hair follicles throughout the body; a pattern that apparently viola tes spatial colinearity. Mice carrying mutant alleles of Hoxc13 have b een generated by gene targeting. Homozygotes have defects in every reg ion in which gene expression is seen. The most striking defect is brit tle hair resulting in alopecia (hairless mice). One explanation for th is novel role is that Hoxc13 has been recruited for a function common to hair, nail, and filiform papilla development.