One gene and one pseudogene for the cytokeratin endo A.

The recombinant cDNA RecXVI, which hybridizes to the endo A mRNA, detects two specific bands on a Southern blot of EcoRI-digested genomic mouse DNA. We have screened a mouse genomic library with this cDNA and isolated these two sequences. Endo A is encoded by a 7.5-kilobase gene and by a 1.6-kilobase pseudogene devoid of introns. A repetitive sequence belonging to the B2 family is located in the third intron of the gene. We have observed that transcription of B2 sequences and of the endo A gene are mutually exclusive.