Elevated myc expression and c-myc amplification in spontaneously occurring B lymphoid cell lines.
Recently, a minor subpopulation of murine B lymphocytes, Ly-1+ B cells, has been distinguished by its unique ontogeny, tissue distribution, and prominence in certain autoimmune and neoplastic B cell diseases. We have previously described a simple murine spleen culture system that results in the spontaneous and exclusive outgrowth of long-term Ly-1+ B cell lines (B Ly-1 cells). Here, we report that the immortal growth property of B Ly-1 cells correlates with a 10-45-fold elevation of steady-state myc RNA and 2-10-fold amplification of the c-myc locus. While c-myc amplification has been observed in malignant cell lines derived from several tissues of origin, its occurrence in lymphoid cells has not been previously reported. The consistent c-myc amplification in B Ly-1 cells may reflect a unique state of this locus in the Ly-1+ B lymphocyte lineage, and contribute to the spontaneous immortalization of this B cell population in vitro, and its apparent predilection for malignant transformation in vivo.
D000818:Animals; D000950:Antigens, Ly / Q000032:analysis; D001402:B-Lymphocytes / Q000032:analysis* / Q000145:classification; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000276:immunology; D005784:Gene Amplification; D051379:Mice; D008805:Mice, Inbred A / Q000235:genetics / Q000276:immunology; D008809:Mice, Inbred C3H / Q000235:genetics / Q000276:immunology; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis* / Q000235:genetics; D016271:Proto-Oncogene Proteins c-myc; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000096:biosynthesis
D000950:Antigens, Ly; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger