Two reactions of Haloferax volcanii RNA splicing enzymes: Joining of exons and circularization of introns

Northern analysis to detect in vivo presence of circular introns. Northern blots of H. volcanii total RNA separated by denaturing 6% (lanes 1–3) and 8% (lanes 4–6) PAGE are hybridized to 5′ ³²P-labeled tRNA^Trp-specific oligonucleotides (marked in Figs. 1A,C). The oligonucleotides used are as follows: H (intron-specific) in lanes 1 and 6, N (circular intron-specific, overlapping splice junction region) in lanes 2 and 5, and B (exon-specific) in lanes 3 and 4. (P) Precursor; CI-6 and CI-8, circular introns in 6% and 8% gels, respectively; LI-6 and LI-8, linear introns in 6% and 8% gels, respectively; t, tRNA.