Sequence heterogeneity at the 5' termini of late simian virus 40 19S and 16S mRNAs

D. Canaani, C. Kahana, A. Mukamel, Y. Groner

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

The 5'-cap-containing leader sequence of the most abundant 19S and 16S mRNAs of simian virus 40 (SV40) was previously mapped between 0.67 and 0.76 map units. We now find tht the two late mRNA species contain multiple 5' ends. Eight different RNase T2-resistant cap structures wer identified: m7GpppmAmpU (47%); m7GpppmAmpUmpU (19%); m7GpppmAmpC (16%); m7GpppmAmpCmpA (5%); m7GppmAmpG (6%); m7GpppGmpC (3%); m7GpppmAmGmpA (2%); m7GpppGmpCmpG (2%). Capped T1 oligonucleotides of 19S and 16S mRNAs have been isolated by two different procedures: (i) chromatography on a DEAE-cellulose column followed by paper electrophoresis and (ii) two-dimensional electrophoresis/homochromatography. Cap structures of the isolated 5' oligonucleotides were identified. Each of the major caps was found to be associated with a few different 5' oligonucleotides, implying a vast heterogeneity at the termini of SV40 late mRNAs. The results suggest that on SV40 DNA, RNA polymerase II has a repertoire of initiation points. In most of the cases, initiation takes place with adenosine triphosphate followed by a pyrimidine. Alternatively, transcription may start at one specific point but a unique mechanism of processing generates heterogeneous populations of termini with a common 5' adenosine triphosphate.

Original languageEnglish
Pages (from-to)3078-3082
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume76
Issue number7
DOIs
StatePublished - 1979
Externally publishedYes

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