G. lamblia uses an unusual poly(A) signal. (A) Nucleotide frequency in the 60-nt window centered on all 2860 validated cleavage sites from this study. (B) Frequency of common poly(A) signals identified in studies of human transcripts (Beaudoing 2000). Sequences 30 nt upstream of cleavage sites from the human RefSeq annotations and validated G. lamblia sites from this study were used to search for common motifs. Plotted is the frequency of each signal in human (left) and G. lamblia (right). (C) MEME analysis of upstream sequences. The same sequences as in B were uploaded to the meme-suite, and a search was conducted for enriched hexamers. Shown is the top motif for human (left) and G. lamblia (right). (D) For all validated cleavage sites containing an AGUAAA motif in the last 40 nt of the mRNA, this bar graph shows the distance between the motif and the end of the read. Distances are counted from the first A of the motif.
