Full Length cDNA of Rat RT1.DMa and RT1.DMb and Expression of RT1.DM Genes in Dendritic and Langerhans Cells

Abstract

MHC encoded DM heterodimers and classical MHC class II complexes meet in an endosomal/lysosomal compartment where DM heterodimers support peptide loading of MHC class II. Studies on peptide loading of rat class II and on peptide persistence in cells of the dendritic lineage prompted us to establish full length cDNA clones coding for the subunits alpha and beta of rat DM molecules as well as a mAb directed against the luminal moiety of the beta subunit. Here we describe the establishment of the first full length cDNA clones of rat RT1.DMa and RT1.DMb. The mode of expression of RT1.DM at the transcript level in bone marrow culture-derived dendritic cells, in Langerhans cells and in a number of additional accessory cells is reported. The beta protein was identified in detergent lysates of RT1.DM expressing cells by Western blot analysis using a newly established monoclonal antibody directed against the luminal part of RT1.DMbeta.

Isolation of Mhc Class II DMA and DMB cDNA Sequences in a Marsupial: The Gray Short-Tailed Opossum (Monodelphis domestica)

“…The Modo-DMB transcript has a long 3ЈUT of 856 bp. Like the 5ЈUT this region has a low similarity to the placental counterparts, which are generally shorter ( (Kelly et al 1991)], cow [Bota (Niimi et al 1995)], mouse [H2 ], rat [RT1 (Kurth et al 1997)], rabbit [Orcu (Hermal et al 1997)], opossum (Modo), and wallaby (Maru). The consensus sequence derived by simple majority is shown using the single-letter IUPAC code.…”

“…The characterization of DM genes in different vertebrate organisms can provide information on the evolution of the Mhc, particularly with regard to the establishment of class II function. To date, gene sequences from placental mammals only, i.e., human, gorilla, chimpanzee, orangutan (Alvarez et al 1998), mouse, rat Kurth et al 1997), cow (Niimi et al 1995), rabbit (Hermal et al 1997), andlemur (O'hUigin andFigueroa 1997), have been reported. In order to gain insights into the evolution of DM and the Mhc, a survey of DM molecules in vertebrates has been initiated.…”