Fig. 5

E. histolytica endogenous sRNA populations and their association with EhAgos. E. histolytica has two endogenous sRNA populations: 27 nt and 31 nt sRNAs. Both largely align to either genomic EhLINEs or a core set of 226 silenced gene loci. These sRNAs have features such as 5′-polyP structure, 5′-G bias, antisense to gene, and not-phased. The 31 nt sRNAs differ from 27 nt sRNAs at the 3′-end with addition of non-templated 3 or 4 As. All three EhAgos associate to 27 nt sRNA populations and these sRNAs are largely overlapping. The 31 nt sRNAs are in partial association with EhAgo2–2 but not with other two EhAgos or mutant EhAgo2–2^△NLS-DR (shown in the boxed area). The functional role of 31 nt sRNAs is linked to sRNA regulation, but the exact underlying mechanism for its biogenesis or function await further study. Red dotted arrows represent sRNAs (either with or without oligo-A tail). Solid black arrows indicate data supported by sRNA sequencing; dashed black two-way arrows with a question mark indicate possible routes for sRNA modification between two sRNA populations, or between 31 nt sRNAs and the EhAgo2–2-loaded 27 nt sRNAs