A neomycin resistance cassette replaced exon 10 of the Xpc gene, and portions of the flanking introns. The authors predict that homozygous mutant animals would produce a truncated polypeptide with 27 missense amino acids in place of the last 300 C-terminal amino acids. Northern analysis of primary MEF cells from homozygous mutant embryos detected two anomalous transcripts using an exon 7-10 probe, and no transcript using an exon 11-15 probe. (J:38645)