Figure 1.

Sequence alignments of U4atac and U6atac snRNAs. The tentative Arabidopsis U4atac snRNA was aligned against the human U4atac snRNA (U62822) using CLUSTAL W [22]. Possible sequence domains are indicated by different background colors, with cyan indicating transcription signals (USE, upstream sequence element; TATA, TATA box), green indicating the region involved in the stem-loop-stem structure, and pink indicating the domain that binds Sm proteins. The corresponding interaction region in U6atac snRNA is also marked in green. Red background indicates G-T base-pairs in the stem-loop structure. Grey letters indicate the genome sequence upstream and downstream of the putative U4atac gene. Asterisks (upper panel) and black shading (lower panel) show conserved positions in the alignment.