Posttranscriptional mechanisms are responsible for accumulation of truncated c-myc RNAs in murine plasma cell tumors.
c-myc Messenger RNAs are known to be extremely unstable (t1/2 = 10 min) in normal and tumor cells, suggesting that degradation could play an important role in regulating their steady state level in the cytoplasm. We have investigated the stabilities of c-myc mRNAs in three murine plasmacytomas, where the c-myc gene either remains intact (ABPC20) or exists in a truncated form (MPC-11 and J558L) subsequent to 6;15 or 12;15 chromosome translocations respectively, and in an A-MuLV-induced pre-B lymphoma line (18-81.5) that lacks chromosome translocations and contains both c-myc genes in their normal context. The truncated myc genes in J558L and MPC-11 lack the promoters of the normal gene but are transcribed from cryptic promoters within the first c-myc intron. We found that posttranscriptional processes are largely responsible for the higher steady state accumulations of truncated c-myc transcripts, while broken and intact c-myc genes are transcribed at comparable rates.
M
M
Piechaczyk
J Q
JQ
Yang
J M
JM
Blanchard
P
P
Jeanteur
K B
KB
Marcu
D000818:Animals; D001402:B-Lymphocytes; D001483:Base Sequence; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D003609:Dactinomycin / Q000494:pharmacology; D006207:Half-Life; D008223:Lymphoma / Q000235:genetics; D051379:Mice; D009693:Nucleic Acid Hybridization; D009857:Oncogenes; D010954:Plasmacytoma / Q000235:genetics; D011401:Promoter Regions, Genetic; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014178:Translocation, Genetic
D012333:RNA, Messenger; D012334:RNA, Neoplasm; D003609:Dactinomycin