Metagenomic sequencing suggests a diversity of RNA interference-like responses to viruses across multicellular eukaryotes (original) (raw)
Fig 4
Small RNAs from DNA parvo/densovirus-like contigs.
Panels to the left show the distribution of 20-30nt small RNAs along the length of the parvo/densovirus-like contigs from sea anemone (A) and starfish (B-E), and panels to the right show the size distribution small RNA reads coloured by the 5' base (U red, G yellow, C blue, A green). Read counts above the x-axis represent reads mapping to the positive sense (coding) sequence, and counts below the x-axis represent reads mapping to the complementary sequence. Only reads from the oxidised library are shown, but other libraries display similar distributions, and the small-RNA ‘hotspot’ pattern is highly repeatable (S6 Fig). For all but one of the parvo/denso-like virus contigs, the small RNAs derived exclusively from the negative sense strand and showed a strong 5'U bias, consistent with piRNAs derived from endogenous copies (see main text). For one contig (B: Millport starfish parvo-like virus 1) reads derived predominantly from the positive strand and did not display a 5' U bias. Although the number of unique small RNA sequences from this virus was small, the positive-sense small RNAs showed a slight bias to A at position 10, consistent with ping-pong (S6 Fig). The data required to plot these size distributions is provided in S5 Table.