Accumulation of Stable Full-Length Circular Group I Intron RNAs during Heat-Shock
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Accumulation of Stable Full-Length Circular Group I Intron RNAs during Heat-Shock. / Andersen, Kasper L.; Beckert, Bertrand; Masquida, Benoit; Johansen, Steinar D.; Nielsen, Henrik.
In: Molecules, Vol. 21, No. 11, 1451, 11.2016.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Accumulation of Stable Full-Length Circular Group I Intron RNAs during Heat-Shock
AU - Andersen, Kasper L.
AU - Beckert, Bertrand
AU - Masquida, Benoit
AU - Johansen, Steinar D.
AU - Nielsen, Henrik
PY - 2016/11
Y1 - 2016/11
N2 - Group I introns in nuclear ribosomal RNA of eukaryotic microorganisms are processed by splicing or circularization. The latter results in formation of full-length circular introns without ligation of the exons and has been proposed to be active in intron mobility. We applied qRT-PCR to estimate the copy number of circular intron RNA from the myxomycete Didymium iridis. In exponentially growing amoebae, the circular introns are nuclear and found in 70 copies per cell. During heat-shock, the circular form is up-regulated to more than 500 copies per cell. The intron harbours two ribozymes that have the potential to linearize the circle. To understand the structural features that maintain circle integrity, we performed chemical and enzymatic probing of the splicing ribozyme combined with molecular modeling to arrive at models of the inactive circular form and its active linear counterpart. We show that the two forms have the same overall structure but differ in key parts, including the catalytic core element P7 and the junctions at which reactions take place. These differences explain the relative stability of the circular species, demonstrate how it is prone to react with a target molecule for circle integration and thus supports the notion that the circular form is a biologically significant molecule possibly with a role in intron mobility
AB - Group I introns in nuclear ribosomal RNA of eukaryotic microorganisms are processed by splicing or circularization. The latter results in formation of full-length circular introns without ligation of the exons and has been proposed to be active in intron mobility. We applied qRT-PCR to estimate the copy number of circular intron RNA from the myxomycete Didymium iridis. In exponentially growing amoebae, the circular introns are nuclear and found in 70 copies per cell. During heat-shock, the circular form is up-regulated to more than 500 copies per cell. The intron harbours two ribozymes that have the potential to linearize the circle. To understand the structural features that maintain circle integrity, we performed chemical and enzymatic probing of the splicing ribozyme combined with molecular modeling to arrive at models of the inactive circular form and its active linear counterpart. We show that the two forms have the same overall structure but differ in key parts, including the catalytic core element P7 and the junctions at which reactions take place. These differences explain the relative stability of the circular species, demonstrate how it is prone to react with a target molecule for circle integration and thus supports the notion that the circular form is a biologically significant molecule possibly with a role in intron mobility
KW - group I intron
KW - Didymium iridis
KW - circular RNA
KW - horizontal gene transfer
KW - molecular modeling
KW - RNA catalysis
U2 - 10.3390/molecules21111451
DO - 10.3390/molecules21111451
M3 - Journal article
C2 - 27809244
VL - 21
JO - Molecules
JF - Molecules
SN - 1420-3049
IS - 11
M1 - 1451
ER -
ID: 170804120