Publications by authors named "Diego Rojas-Benitez"

Transfer RNAs (tRNAs) are the most post-transcriptionally modified RNA species. Some of these modifications, especially the ones located in the anti-codon loop, are required for decoding capabilities of tRNAs. Such is the case for 5-methoxy-carbonyl-methyl-2-thio-uridine (mcmsU), synthetized by the Elongator complex.

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The study of spinal cord regeneration using diverse animal models, which range from null to robust regenerative capabilities, is imperative for understanding how regeneration evolved and, eventually, to treat spinal cord injury and paralysis in humans. In this study, we used electroablation to fully transect the spinal cord of zebrafish larvae (3 days postfertilization) and examined regeneration of the tissue over time. We used transgenic lines to follow immune cells, oligodendrocytes, and neurons in vivo during the entire regenerative process.

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Article Synopsis
  • Endoribonuclease toxins, or ribotoxins, are produced by bacteria and fungi to deal with stress, outcompete other species, or combat viruses.
  • PrrC, a bacterial ribotoxin, specifically targets and cuts tRNA at the anticodon loop, with in vitro studies indicating that a modification called threonylcarbamoyl adenosine (tA) is crucial for its function, although this had not been proven in living organisms.
  • Using a new sensitive detection method, researchers found that while a Streptococcus mutans mutant lacking the normal tA synthesis gene (tsaE) had significantly less tA (93% less), it was still present, indicating tA is not essential for S
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Transfer RNAs (tRNAs) harbor a subset of post-transcriptional modifications required for structural stability or decoding function. N6-threonylcarbamoyladenosine (t6A) is a universally conserved modification found at position 37 in tRNA that pair A-starting codons (ANN) and is required for proper translation initiation and to prevent frame shift during elongation. In its absence, the synthesis of aberrant proteins is likely, evidenced by the formation of protein aggregates.

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The universal tRNA modification tA is found at position 37 of nearly all tRNAs decoding ANN codons. The absence of tA leads to severe growth defects in baker's yeast, phenotypes similar to those caused by defects in mcmsU synthesis. Mutants in mcmsU can be suppressed by overexpression of tRNA, but we show tA phenotypes could not be suppressed by expressing any individual ANN decoding tRNA, and tA and mcmsU are not determinants for each other's formation.

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N(6)-Threonylcarbamoyl-adenosine (t(6)A) is a universal modification occurring at position 37 in nearly all tRNAs that decode A-starting codons, including the eukaryotic initiator tRNA (tRNAi (Met)). Yeast lacking central components of the t(6)A synthesis machinery, such as Tcs3p (Kae1p) or Tcs5p (Bud32p), show slow-growth phenotypes. In the present work, we show that loss of the Drosophila tcs3 homolog also leads to a severe reduction in size and demonstrate, for the first time in a non-microbe, that Tcs3 is required for t(6)A synthesis.

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The TOR signaling pathway is crucial in the translation of nutritional inputs into the protein synthesis machinery regulation, allowing animal growth. We recently identified the Bud32 (yeast)/PRPK (human) ortholog in Drosophila, Prpk (p53-related protein kinase), and found that it is required for TOR kinase activity. Bud32/PRPK is an ancient and atypical kinase conserved in evolution from Archeae to humans, being essential for Archeae.

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Germ cell apoptosis is important to regulate sperm production in the mammalian testis, but the molecular mechanisms underlying apoptosis are still poorly understood. We have recently shown that in vitro, etoposide induces upregulation of TACE/ADAM17 and ADAM10, two membrane-bound extracellular metalloproteases. Here we show that in vivo these enzymes are involved in etoposide-, but not in heat shock-, induced apoptosis in rat spermatogenesis.

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The pathways leading to male germ cell apoptosis in vivo are poorly understood, but are highly relevant for the comprehension of sperm production regulation by the testis. In this work, we show the evidence of a mechanism where germ cell apoptosis is induced through the inactivation and shedding of the extracellular domain of KIT (c-kit) by the protease TACE/a disintegrin and metalloprotease 17 (ADAM17) during the first wave of spermatogenesis in the rat. We show that germ cells undergoing apoptosis lacked the extracellular domain of the KIT receptor.

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