The bI4 group I intron binds directly to both its protein splicing partners, a tRNA synthetase and maturase, to facilitate RNA splicing activity
The imported mitochondrial leucyl-tRNA synthetase (NAM2p) and a mitochondrial-expressed intron-encoded maturase protein are required for splicing the fourth intron (bI4) of the yeast cob gene, which expresses an electron transfer protein that is essential to respiration. However, the role of the tRN...
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Veröffentlicht in: | RNA (Cambridge) 2000-12, Vol.6 (12), p.1882-1894, Article S1355838200001254 |
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Zusammenfassung: | The imported mitochondrial leucyl-tRNA synthetase
(NAM2p) and a mitochondrial-expressed intron-encoded maturase
protein are required for splicing the fourth intron (bI4)
of the yeast cob gene, which expresses an electron
transfer protein that is essential to respiration. However,
the role of the tRNA synthetase, as well as the function
of the bI4 maturase, remain unclear. As a first step towards
elucidating the mechanistic role of these protein splicing
factors in this group I intron splicing reaction, we tested
the hypothesis that both leucyl-tRNA synthetase and bI4
maturase interact directly with the bI4 intron. We developed
a yeast three-hybrid system and determined that both the
tRNA synthetase and bI4 maturase can bind directly and
independently via RNA–protein interactions to the
large bI4 group I intron. We also showed, using modified
two-hybrid and three-hybrid assays, that the bI4 intron
bridges interactions between the two protein splicing partners.
In the presence of either the bI4 maturase or the Leu-tRNA
synthetase, bI4 intron transcribed recombinantly with flanking
exons in the yeast nucleus exhibited splicing activity.
These data combined with previous genetic results are consistent
with a novel model for a ternary splicing complex (two
protein: one RNA) in which both protein splicing partners
bind directly to the bI4 intron and facilitate its self-splicing
activity. |
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ISSN: | 1355-8382 1469-9001 |
DOI: | 10.1017/S1355838200001254 |