International Mammalian Genome Society

logo18th International Mouse Genome Conference

17-22 October 2004, Seattle, USA


POSTER 43 - MOUSE HAIRY EARS (EH) INVERSION MUTATION DISRUPTS NO GENE TRANSCRIPTS, BUT EXPRESSION OF HOXC GENES IN SKIN IS DISTURBED

Mentzer S 1, Sundberg J 2, Cacheiro N 1, Chao H 3, Carpenter D 1, Johnson D 1, Rinchik E 3, You Y  1

1 Oak Ridge National Laboratory, Oak Ridge, United States, 2 The Jackson Laboratory, Bar Harbor, United States, 3 University of Tennessee, Knoxville, United States

The mouse Hairy Ears (Eh) mutation is a paracentric inversion, In(15)Eh2Rl, in the distal half of Chr 15.  Heterozygous Eh/+ mice have small and hairy ears, whereas Eh/Eh homozygotes in C3H/Rl background typically die before weaning.  We mapped both the proximal and distal inversion breakpoints to BAC clones using fluorescent in situ hybridization (FISH) on metaphase Eh/+ cell spreads, cloned the distal breakpoint, and determined inversion breakpoint sequences.  Consequently, genes surrounding the inversion breakpoints were identified.  No protein-coding transcripts are disrupted by either inversion breakpoints.  The proximal breakpoint occurs between Sntb1 (syntrophin  1, centromerically) and Has2 (hyaluronan synthase 2, telomerically), while the distal breakpoint takes place between the Hoxc4 (Homeobox C4, centromerically) and an uncharacterized transcript (GenBank accession numbers: BF606930 and AK019974, telomerically).  Therefore the inversion spans ~47 Mb. Quantitative RNA analysis by TaqMan real-time PCR assay for the Hoxc genes indicated that expression of many members of Hoxc has been changed in skin during skin/hair morphogenesis and in adult mice.  Hair fiber analysis using scanning electron microscopy revealed that ear-specific hair fibers grow longer in the ears of the Eh mutation.  Histology analysis of ear-skin did not reveal any obvious abnormalities.  Taken together, our results suggest that Hoxc genes play important roles in hair growth.

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