The most abundant nascent poly(A) + RNAs are transcribed by RNA polymerase III in murine tumor cells.
Twelve to twenty percent of newly synthesized poly(A) + RNA is transcribed by RNA polymerase III in Ehrlich ascites carcinoma and P3O1 plasmocytoma mouse tumors. Most of this RNA designated as pol IIIpoly(A) + RNA has a size of 160 to 800 nucleotides with a maximum of distribution of ca. 300 nucleotides. Pol IIIpoly(A) + RNA fraction consists of two major classes of molecules corresponding to previously described B1 RNA and B2 RNA with the ratio of 1:4 to 2:3. All B2 RNAs present in poly(A) + fraction contain a long poly(A) segments at the 3' ends. Thus, RNA polymerase III transcripts can be polyadenylated. Several transcripts that hybridize with B2 probe were also observed in poly(A)- RNA. The major components consist of 180, 160, 120 and 95 nucleotides. The 180-nucleotide B2 RNA seems to be a primary transcript from B2 repeat. We suggest that other B2 RNAs are transcribed from truncated copies of B2 element.
Kramerov
D A
DA
Engelhardt Institute of Molecular Biology, USSR Academy of Sciences, Moscow.
Tillib
S V
SV
Shumyatsky
G P
GP
Georgiev
G P
GP
D000818:Animals; D002286:Carcinoma, Ehrlich Tumor; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004587:Electrophoresis, Agar Gel; D004591:Electrophoresis, Polyacrylamide Gel; D051379:Mice; D008970:Molecular Weight; D009710:Nucleotide Mapping; D011061:Poly A / Q000235:genetics* / Q000378:metabolism; D012313:RNA / Q000235:genetics* / Q000378:metabolism; D012320:RNA Polymerase III / Q000378:metabolism*; D012333:RNA, Messenger; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured; D014461:Ultracentrifugation
D012333:RNA, Messenger; D011061:Poly A; D012313:RNA; D012321:DNA-Directed RNA Polymerases; D012320:RNA Polymerase III