Characterization of immunoglobulin mrna expression in burkitt lymphoma cell lines

Publisher Website
Google Scholar
Abstract
Immunoglobulin heavy‐ and light‐chain mRNA of II Burkitt lymphoma (BL) cell lines (9 African and 2 American) were analyzed for various structural characteristics. In agreement with previous results at the protein level, all the BL cell lines express heavy‐chain mRNA transcripts of the μ class. Surprisingly, a high μ/μm mRNA ratio was found in 2 lgM‐producing BL cell lines (Raji and CCL85), that do not secrete immunoglobulin. Variable region gene use was also assessed in the cell lines: while 4 out of 7 endemic BL cell lines use VH genes that belong to the VH3 gene family, no clear bias in the expression of particular VH or VL gene families among this sampling of BL lines was found. Northern blot analysis of immunoglobulin transcripts in endemic BL cell lines did show that 2 such lines (AG876 and HTB62) expressed truncated heavy‐chain transcripts; RNA sequence analysis of the VH region demonstrated different abnormal 5‐localized RNA splicing events for the 2 shortened μ transcripts. The light‐chain mRNA in these 2 cell lines also showed structural abnormalities and, in the case of HTB62, 3 different K light‐chain transcripts are produced (of elongated, native and truncated sizes). In vitro translation of mRNA from HTB62 showed μ and K chain proteins corresponding with the relative size for each message.