Transcripts synthesized by RNA polymerase III can be polyadenylated in an AAUAAA-dependent manner

  1. Olga R. Borodulina and
  2. Dmitri A. Kramerov
  1. Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia

Abstract

It is well known that nearly all eukaryotic mRNAs contain a 3′ poly(A) tail. A polyadenylation signal (AAUAAA) nearby the 3′ end of pre-mRNA is required for poly(A) synthesis. The protein complex involved in the pre-mRNA polyadenylation is coupled with RNA polymerase II during the transcription of a gene. According to the commonly accepted view, only RNAs synthesized by RNA polymerase II can be polyadenylated in an AAUAAA-dependent manner. Here we report the polyadenylation of short interspersed elements (SINEs) B2 and VES transcripts generated by RNA polymerase III. HeLa cells were transfected with SINE constructs with or without polyadenylation signals. The analyses of the SINE transcripts showed that only the RNAs with the AAUAAA-signal contained poly(A) tails. Polyadenylated B2 RNA was found to be much more stable in cells than B2 RNA without a poly(A) tail.

Keywords

Footnotes

  • 1 SINEs or short retroposons are repetitive 80- to 400-bp sequences that are interspersed over the eukaryotic genomes and are amplified via reverse transcription (Weiner 2002; Kramerov and Vassetzky 2005; Ohshima and Okada 2005). The genome of mammalian species usually contains two to four families of SINEs, each represented by 104 to 106 copies. Commonly their nucleotide sequences have a 65%–90% similarity. SINEs are transcribed by pol III owing to the promoter in their 5′ region. The classical SINE promoter consists of two boxes (A and B) spaced by 30–40 bp. SINEs belong to nonautonomous mobile elements since they encode no enzymes and utilize the reverse transcriptase of LINEs (long interspersed elements) for their amplification. Most mammalian SINEs proliferate with the help of LINE-1.

  • Reprint requests to: Dmitri A. Kramerov, Engelhardt Institute of Molecular Biology, 32 Vavilov Street, Moscow, 119991, Russia; e-mail: kramerov{at}eimb.ru; fax: 7-499-1351405.

  • Article published online ahead of print. Article and publication date are at http://www.rnajournal.org/cgi/doi/10.1261/rna.1006608.

    • Received January 15, 2008.
    • Accepted June 9, 2008.
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