A 104 nucleotide-long small RNA, referred to as s-poly A+ RNA, containing 30 
adenosine residues on its 3' -end was found in dinoflagellates, purified and its 
nucleotide sequence was determined. The sequence is: (sequence text) The 
polyadenylation signal AAUAAA was not found in this RNA; this result indicates 
that the 30 nucleotide-long poly A on the 3' -end is either coded for by this 
gene, or the poly A chain is added on this small RNA by a mechanism different 
from that for polyadenylation of messenger RNAs. Two polyadenylated small RNAs 
identified previously were implicated in differentiation of chicken heart muscle 
cells (Deshpande, A. K., Jakowlew, S. B., Arnold, H., Crawford, P. A. and 
Siddiqui, M. A. Q. (1977) J. Biol. Chem. 252, 6521-6527), and in brain specific 
mRNA transcription (Sutcliffe, J. G., Milner, R. J., Gottesfeld, J. M. and 
Lerner, R. A. (1984) Nature 309, 237-241). This RNA is the first polyadenylated 
small RNA to be sequenced.