tRNA-like recognition of group I introns by a tyrosyl-tRNA synthetase

Myers, Christopher A.; Kuhla, Birte; Cusack, Stephen; Lambowitz, Alan M.

doi:10.1073/pnas.052596299

Cited by 38 publications

(32 citation statements)

References 32 publications

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“…In the cases of two tRNA synthetases, it has been found that their splicing activity is indeed related to their primary functions. The N. crassa mt tyrosyl RS facilitates splicing of a number of mt group I introns by binding to the intron core via its tRNA binding surface (Caprara et al 1996;Myers et al 2002). Likewise, the S. cerevisiae mt leucyl RS, which is involved in the processing of at least two mt yeast introns, promotes splicing via a domain that functions in the editing of misactivated amino acids and binding of the tRNA acceptor helix (Herbert et al 1988;Li et al 1996;Rho et al 2002).…”

Section: Evolutionary Perspectivementioning

confidence: 99%

A C-terminal fragment of an intron-encoded maturase is sufficient for promoting group I intron splicing

Downing

Brady²,

Caprara³

2005

RNA

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Group I introns often encode proteins that catalyze site-specific DNA hydrolysis. Some of these proteins have acquired the ability to promote splicing of their cognate intron, but whether these two activities reside in different regions of the protein remains obscure. A crystal structure of I-AniI, a dual function intron-encoded protein, has shown that the protein has two pseudo-symmetric domains of equal size. Each domain contacts its DNA substrate on either side of two cleavage sites. As a first step to identify the RNA binding surface, the N-and C-terminal domains of I-AniI were separately expressed and tested for promoting the splicing of the mitochondrial (mt) COB pre-RNA. The N-terminal protein showed no splicing activation or RNA binding, suggesting that this domain plays a minimal role in activity or is improperly folded. Remarkably, the 16-kDa C-terminal half facilitates intron splicing with a rate similar to that of the full-length protein. Both the C-terminal fragment and full-length proteins bind tightly to the COB intron. RNase footprinting shows that the C-terminal and full-length proteins bind to the same regions and induce the same conformational changes in the COB intron. Together, these results show that the C-terminal fragment of I-AniI is necessary and sufficient for maturase activity and suggests that I-AniI acquired splicing function by utilizing a relatively small protein surface that likely represents a novel RNA binding motif. This fragment of I-AniI represents the smallest group I intron splicing cofactor described to date.

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Section: Evolutionary Perspectivementioning

confidence: 99%

A C-terminal fragment of an intron-encoded maturase is sufficient for promoting group I intron splicing

Downing

Brady²,

Caprara³

2005

RNA

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“…The results of an experiment using buffer conditions favoring Cyt-18 activity (Guo and Lambowitz 1992) are shown. A representative gel including the ⌬ORF mtLSU positive control intron RNA (Myers et al 2002) and two S788 intron RNAs (Acarospora and Lecanora) incubated in the presence (+) or absence (−) of Cyt-18 are presented. For the ⌬ORF mtLSU intron precursor RNAs (Pre), ligated exons RNAs (LE), and excised intron RNAs (Int) are readily seen.…”

Section: Parallel Evolution Of Fungal Rdna Group I and Spliceosomal Imentioning

confidence: 99%

Long-term evolution of the S788 fungal nuclear small subunit rRNA group I introns

Haugen¹,

Runge²,

Bhattacharya³

2004

RNA

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More than 1000 group I introns have been identified in fungal rDNA. Little is known, however, of the splicing and secondary structure evolution of these ribozymes. Here, we use a combination of comparative and biochemical methods to address the evolution and splicing of a vertically inherited group I intron found at position 788 in the fungal small subunit (S) rRNA. The ancestral state of the S788 intron contains a highly conserved core and an extended P5 domain typical of IC1 introns. In contrast, the more derived introns have lost most of P5, and have an accelerated divergence rate within the core region with three functionally important substitutions that unambiguously separate them from the ancestral pool. Of 14 S788 group I introns that were tested for splicing, five, all of the ancestral type, were able to self-splice and produced intron RNA circles in vitro. The more derived S788 introns did not self-splice, and potentially rely on fungal-specific factors to facilitate splicing. In summary, we demonstrate one possible fate of vertically inherited group I introns, the loss of secondary structure elements, lessened selective constraints in the intron core, and ultimately, dependence on host-mediated splicing.

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“…The Neurospora crassa mitochondrial (mt) tyrosyl-tRNA synthetase (TyrRS), the CYT-18 protein, functions in splicing group I introns by stabilizing the catalytically active RNA structure (Akins and Lambowitz 1987;Guo and Lambowitz 1992;Mohr et al 1992;Caprara et al 1996a,b;Myers et al 2002). The group I intron catalytic core consists of two extended helical domains, one formed by the coaxial stacking of secondary structure elements P5, P4, and P6 (P4-P6 domain) and the other consisting of P8, P3, P7, and P9 (P3-P9 domain; Michel and Westhof 1990;Cech 1993;Golden et al 1998).…”

Section: Introductionmentioning

confidence: 99%

“…CYT-18 interacts with the group I intron catalytic core on the side opposite the active-site cleft (Caprara et al 1996b). Biochemical and genetic studies have led to a model in which CYT-18 binds first to the P4-P6 domain to promote its assembly and then makes additional contacts with the P3-P9 domain to stabilize the two major RNA helical domains in the correct relative orientation to form the intron's active site (Caprara et al 1996a,b;Webb et al 2001;Myers et al 2002).…”

Section: Introductionmentioning

confidence: 99%

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The Neurospora crassa CYT-18 protein C-terminal RNA-binding domain helps stabilize interdomain tertiary interactions in group I introns

Chen¹,

Mohr²,

Lambowitz

2004

RNA

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The Neurospora crassa mitochondrial tyrosyl-tRNA synthetase (CYT-18 protein) promotes the splicing of group I introns by stabilizing the catalytically active RNA structure. To accomplish this, CYT-18 recognizes conserved structural features of group I intron RNAs using regions of the N-terminal nucleotide-binding fold, intermediate ␣-helical, and C-terminal RNA-binding domains that also function in binding tRNA

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tRNA-like recognition of group I introns by a tyrosyl-tRNA synthetase

Cited by 38 publications

References 32 publications

A C-terminal fragment of an intron-encoded maturase is sufficient for promoting group I intron splicing

A C-terminal fragment of an intron-encoded maturase is sufficient for promoting group I intron splicing

Long-term evolution of the S788 fungal nuclear small subunit rRNA group I introns

The Neurospora crassa CYT-18 protein C-terminal RNA-binding domain helps stabilize interdomain tertiary interactions in group I introns

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