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.