title: The absence of beta 2-microglobulin in Daudi cells: active gene but inactive messenger RNA.
abstract: The Daudi cell line is characterized by an absence of HLA antigen on its surface. This has been attributed to a lack of beta 2-microglobulin (beta 2m) while the heavy chain of HLA is present intracellularly. Karyotype analysis of Daudi cells has shown a deletion involving one of the beta 2-microglobulin alleles. It was generally believed that the absence of beta 2-microglobulin in that cell line resulted from an absence of expression of the remaining gene. We report here the unexpected finding of a normal amount of beta 2-microglobulin messenger RNA in Daudi cells. This was demonstrated by "Northern blot" hybridization with cDNA plasmid clones as a probe. This mRNA, however, when purified by hybridization-selection with beta 2-microglobulin plasmid DNA, is unable to function as messenger in protein synthesis and is therefore an inactive mRNA. The finding of a translationally inactive beta 2-microglobulin mRNA provides a new explanation for the absence of beta 2-microglobulin and therefore of HLA antigens in Daudi cells.
mesh_terms: D000818:Animals; D001609:Beta-Globulins / Q000235:genetics*; D002051:Burkitt Lymphoma / Q000235:genetics*; D002460:Cell Line; D006680:HLA Antigens / Q000235:genetics; D006801:Humans; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics / Q000502:physiology*; D001613:beta 2-Microglobulin / Q000235:genetics*
chemical_list: D001609:Beta-Globulins; D006680:HLA Antigens; D012333:RNA, Messenger; D001613:beta 2-Microglobulin