TY - JOUR

T1 - The group I-like ribozyme DiGIR1 mediates alternative processing of pre-rRNA transcripts in Didymium iridis

AU - Vader, Anna

AU - Johansen, Steinar

AU - Nielsen, Henrik

N1 - Keywords: Alternative Splicing; Base Sequence; Catalysis; DNA Primers; Introns; Myxomycetes; RNA Precursors; RNA, Catalytic; RNA, Fungal; RNA, Ribosomal

PY - 2002

Y1 - 2002

N2 - During starvation induced encystment, cells of the myxomycete Didymium iridis accumulate a 7.5-kb RNA that is the result of alternative processing of pre-rRNA. The 5' end corresponds to an internal processing site cleaved by the group I-like ribozyme DiGIR1, located within the twin-ribozyme intron Dir.S956-1. The RNA retains the majority of Dir.S956-1 including the homing endonuclease gene and a small spliceosomal intron, the internal transcribed spacers ITS1 and ITS2, and the large subunit rRNA lacking its two group I introns. The formation of this RNA implies cleavage by DiGIR1 in a new RNA context, and presents a new example of the cost to the host of intron load. This is because the formation of the 7.5-kb RNA is incompatible with the formation of functional ribosomal RNA from the same transcript. In the formation of the 7.5-kb RNA, DiGIR1 catalysed cleavage takes place without prior splicing performed by DiGIR2. This contrasts with the processing order leading to mature rRNA and I-DirI mRNA in growing cells, suggesting an interplay between the two ribozymes of a twin-ribozyme intron.

AB - During starvation induced encystment, cells of the myxomycete Didymium iridis accumulate a 7.5-kb RNA that is the result of alternative processing of pre-rRNA. The 5' end corresponds to an internal processing site cleaved by the group I-like ribozyme DiGIR1, located within the twin-ribozyme intron Dir.S956-1. The RNA retains the majority of Dir.S956-1 including the homing endonuclease gene and a small spliceosomal intron, the internal transcribed spacers ITS1 and ITS2, and the large subunit rRNA lacking its two group I introns. The formation of this RNA implies cleavage by DiGIR1 in a new RNA context, and presents a new example of the cost to the host of intron load. This is because the formation of the 7.5-kb RNA is incompatible with the formation of functional ribosomal RNA from the same transcript. In the formation of the 7.5-kb RNA, DiGIR1 catalysed cleavage takes place without prior splicing performed by DiGIR2. This contrasts with the processing order leading to mature rRNA and I-DirI mRNA in growing cells, suggesting an interplay between the two ribozymes of a twin-ribozyme intron.

M3 - Journal article

C2 - 12444968

VL - 269

SP - 5804

EP - 5812

JO - FEBS Journal

JF - FEBS Journal

SN - 1742-464X

IS - 23

ER -