Secondary structure of Alu and Alu-like RNA. (A) Secondary structure of 7SL RNA as determined by enzymatic digestions (Sinnett et al. 1991) and adapted from work by Häsler and Strub (2006). The RNA is segmented into Alu and S domains. SRP9/SRP14 recognize the Alu domain, while SRP19, SRP54, and SRP68/SRP72 recognize the S domain. (B) Predicted secondary structure of BC200 RNA based on conservation of secondary structure motifs compared to 7SL RNA (Labuda and Zitkiewicz 1994). The structure is composed of an Alu domain followed by a polyadenosine tract and a unique sequence. (C) Secondary structure of an AluY RNA found on intron four of the α-fetoprotein gene based on enzymatic digestions of an Alu RNA (Sinnett et al. 1991) and adapted from Häsler and Strub (2006). The structure is composed of two distinct arms with a demarcating internal polyadenosine tract.
