Lack of effective messenger RNA for beta 2-microglobulin in a gestational human choriocarcinoma cell line (GCH-1).

When two lines of gestational human choriocarcinoma cells (GCH-1 and GCH-2) were incubated with [35S]methionine, the labeled beta 2-microglobulin was not detected on sodium dodecyl sulfate:polyacrylamide gel electrophoresis after purification of the labeled protein with affinity chromatography, using rabbit antibody against beta 2-microglobulin as the ligand. In contrast, in the case of nongestational choriocarcinoma cells originating from male stomach cells, the incorporation of [35S]methionine into beta 2-microglobulin was observed. When polyadenylate-containing messenger RNA prepared from GCH-1 cells was incubated with [35S]methionine in a rabbit reticulocyte lysate system, the labeling of beta 2-microglobulin was not shown. On the other hand, when polyadenylate-containing messenger RNA from nongestational choriocarcinoma cells was incubated in the same cell-free system, labeled beta 2-microglobulin was detected. These results indicate that beta 2-microglobulin is not synthesized in gestational human choriocarcinoma cells and at least in the case of GCH-1, beta 2-microglobulin is not synthesized owing to the lack of effective messenger RNA for beta 2-microglobulin.