CHARACTERIZATION AND MAPPING OF THE GENE ENCODING MOUSE PROTEASOME SUBUNIT-DELTA (LMP19)

The proteasome subunit DELTA is unusually closely related to the major histocompatibility complex (MHC)-linked proteasome subunit, LMP2. The sequence of a mouse cDNA for DELTA confirms that this 22100 M(r) prot easome subunit is highly conserved across species, Sequence analysis o f the mouse gene encoding DELTA, designated Lmp19, indicates that it c onsists of six exons and five introns, similar to the Lmp2 gene. The 5 ' upstream region lacks a TATA regulatory sequence, which is also abse nt from proteasome genes isolated from Drosophila. BXD recombinant inb red (RI) mice were used to map the potential chromosomal location of L mp19, and revealed that the DELTA subunit has related sequences presen t on two different mouse chromosomes, chromosomes 1 and 11. Typing of 89 progeny from a C57BL/6J X Mus spretus DNA backcross panel (BSS) con firmed the chromosome 1 assignment. Southern hybridization with a poly merase chain reaction-generated Lmpl9 intron 2-specific probe indicate s that the Lmpl9 genomic clone corresponds to the sequence on chromoso me 11, and further suggests that the chromosome 1 copy represents a pr ocessed pseudogene (Lmp19-ps1).