Prevalent and distinct spliceosomal 3′-end processing mechanisms for fungal telomerase RNA
نویسندگان
چکیده
Telomerase RNA (TER) is an essential component of the telomerase ribonucleoprotein complex. The mechanism for TER 3'-end processing is highly divergent among different organisms. Here we report a unique spliceosome-mediated TER 3'-end cleavage mechanism in Neurospora crassa that is distinct from that found specifically in the fission yeast Schizosaccharomyces pombe. While the S. pombe TER intron contains the canonical 5'-splice site GUAUGU, the N. crassa TER intron contains a non-canonical 5'-splice site AUAAGU that alone prevents the second step of splicing and promotes spliceosomal cleavage. The unique N. crassa TER 5'-splice site sequence is evolutionarily conserved in TERs from Pezizomycotina and early branching Taphrinomycotina species. This suggests that the widespread and basal N. crassa-type spliceosomal cleavage mechanism is more ancestral than the S. pombe-type. The discovery of a prevalent, yet distinct, spliceosomal cleavage mechanism throughout diverse fungal clades furthers our understanding of TER evolution and non-coding RNA processing.
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Diverse mechanisms for spliceosome-mediated 3′ end processing of telomerase RNA
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