Divergent Evolution of Eukaryotic CC- and A-Adding Enzymes

Erber, Lieselotte; Franz, Paul; Betat, Heike; Prohaska, Sonja J.; Mörl, Mario

doi:10.3390/ijms21020462

Cited by 5 publications

(8 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While most organisms rely on the existence of a single CCA-adding enzyme for synthesis and maintenance of functional tRNA 3′-ends, many bacteria are known that carry two collaborating enzymes with partial activities for CC- and A-addition [ 26 , 27 , 28 , 55 , 56 ]. Recently, eukaryotes with split CC- and A-adding activities have also been described [ 23 , 24 , 25 ]. Hence, it is very surprising that D. discoideum encodes a pair of two bona-fide CCA-adding enzymes (CCA1 and CCA2) with redundant activities where a single enzyme would be sufficient.…”

Section: Discussionmentioning

confidence: 99%

Unusual Occurrence of Two Bona-Fide CCA-Adding Enzymes in Dictyostelium discoideum

Erber

Hoffmann

Fallmann

et al. 2020

IJMS

Self Cite

View full text Add to dashboard Cite

Dictyostelium discoideum, the model organism for the evolutionary supergroup of Amoebozoa, is a social amoeba that, upon starvation, undergoes transition from a unicellular to a multicellular organism. In its genome, we identified two genes encoding for tRNA nucleotidyltransferases. Such pairs of tRNA nucleotidyltransferases usually represent collaborating partial activities catalyzing CC- and A-addition to the tRNA 3′-end, respectively. In D. discoideum, however, both enzymes exhibit identical activities, representing bona-fide CCA-adding enzymes. Detailed characterization of the corresponding activities revealed that both enzymes seem to be essential and are regulated inversely during different developmental stages of D. discoideum. Intriguingly, this is the first description of two functionally equivalent CCA-adding enzymes using the same set of tRNAs and showing a similar distribution within the cell. This situation seems to be a common feature in Dictyostelia, as other members of this phylum carry similar pairs of tRNA nucleotidyltransferase genes in their genome.

show abstract

Section: Discussionmentioning

confidence: 99%

Unusual Occurrence of Two Bona-Fide CCA-Adding Enzymes in Dictyostelium discoideum

Erber

Hoffmann

Fallmann

et al. 2020

IJMS

Self Cite

View full text Add to dashboard Cite

show abstract

“…Together with the lack of the basic/acidic motif (B/A) and the deletion of the flexible loop—hallmarks for CC-adding enzymes ( Neuenfeldt et al. 2008 ; Erber, Franz et al. 2020 )—this sequence deviation indicates that Ntr3 likely represents a CC-adding activity.…”

Section: Resultsmentioning

confidence: 99%

“…2019 ; Reid et al. 2019 ; Erber, Franz et al. 2020 ), the existence of enzymes with split activity in A. castellanii is surprising considering that this organism already possesses two CCA-adding enzymes.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

CCA-Addition Gone Wild: Unusual Occurrence and Phylogeny of Four Different tRNA Nucleotidyltransferases in Acanthamoeba castellanii

Erber

Betat

Mörl

2020

Molecular Biology and Evolution

Self Cite

View full text Add to dashboard Cite

tRNAs are important players in the protein synthesis machinery, where they act as adapter molecules for translating the mRNA codons into the corresponding amino acid sequence. In a series of highly conserved maturation steps, the primary transcripts are converted into mature tRNAs. In the amoebozoan Acanthamoeba castellanii, a highly unusual evolution of some of these processing steps was identified that are based on unconventional RNA polymerase activities. In this context, we investigated the synthesis of the 3’-terminal CCA-end that is added posttranscriptionally by a specialized polymerase, the tRNA nucleotidyltransferase (CCA-adding enzyme). The majority of eukaryotic organisms carry only a single gene for a CCA-adding enzyme that acts on both the cytosolic as well as the mitochondrial tRNA pool. In a bioinformatic analysis of the genome of this organism, we identified a surprising multitude of genes for enzymes that contain the active site signature of eukaryotic/eubacterial tRNA nucleotidyltransferases. In vitro activity analyses of these enzymes revealed that two proteins represent bona fide CCA-adding enzymes, one of them carrying an N-terminal sequence corresponding to a putative mitochondrial target signal. The other enzymes have restricted activities and represent CC- and A-adding enzymes, respectively. The A–adding enzyme is of particular interest, as its sequence is closely related to corresponding enzymes from Proteobacteria, indicating a horizontal gene transfer. Interestingly, this unusual diversity of nucleotidyltransferase genes is not restricted to A. castellanii, but is also present in other members of the Acanthamoeba genus, indicating an ancient evolutionary trait.

show abstract

“…Together with the corresponding enzymes from E. coli (EcoCCA; an organism exclusively carrying conventional cloverleaf-like tRNAs) and H. sapiens (HsaCCA; an organism carrying conventional cytosolic as well as moderately reduced mt-tRNAs), the purified enzyme was tested in vitro for activity. As substrates, three different radioactively labeled tRNA transcripts were generated by in vitro transcription (Figure 2A), as it is well established that tRNA nucleotidyltransferases from all kingdoms readily accept in vitro transcripts lacking base modifications (Okabe et al, 2003;Hoffmeier et al, 2010;Ernst et al, 2018;Erber et al, 2020).…”

Section: Rcucca Adds a Complete Cca-triplet To Armless And Canonical mentioning

confidence: 99%

Adaptation of theRomanomermis culicivoraxCCA-adding enzyme to miniaturized armless tRNA substrates

Hennig

Philipp

Bonin

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

AbstractThe mitochondrial genome of the nematode Romanomermis culicivorax encodes for miniaturized hairpin-like tRNA molecules that lack D- as well as T-arms, strongly deviating from the consensus cloverleaf. The single tRNA nucleotidyltransferase of this organism is fully active on armless tRNAs, while the human counterpart is not able to add a complete CCA-end. Transplanting single regions of the Romanomermis enzyme into the human counterpart, we identified a beta-turn element of the catalytic core that – when inserted into the human enzyme - confers full CCA-adding activity on armless tRNAs. This region, originally identified to position the 3’-end of the tRNA primer in the catalytic core, dramatically increases the enzyme’s substrate affinity. While conventional tRNA substrates bind to the enzyme by interactions with the T-arm, this is not possible in the case of armless tRNAs, and the strong contribution of the beta-turn compensates for an otherwise too weak interaction required for the addition of a complete CCA-terminus. This compensation demonstrates the remarkable evolutionary plasticity of the catalytic core elements of this enzyme to adapt to unconventional tRNA substrates.

show abstract

Divergent Evolution of Eukaryotic CC- and A-Adding Enzymes

Cited by 5 publications

References 68 publications

Unusual Occurrence of Two Bona-Fide CCA-Adding Enzymes in Dictyostelium discoideum

Unusual Occurrence of Two Bona-Fide CCA-Adding Enzymes in Dictyostelium discoideum

CCA-Addition Gone Wild: Unusual Occurrence and Phylogeny of Four Different tRNA Nucleotidyltransferases in Acanthamoeba castellanii

Adaptation of theRomanomermis culicivoraxCCA-adding enzyme to miniaturized armless tRNA substrates

Contact Info

Product

Resources

About