The copper-inducible copAB operon in Xanthomonas citri subsp. citri is regulated at transcriptional and translational levels

Autor(es)

de Freitas, Eliane Cristina ^[1] ; Ucci, Amanda Piovesan ^[1] ; Teixeira, Elaine Cristina ^[1] ; Pedroso, Gisele Audrei ^[1] ; Hilario, Eduardo ^{[2, 1]} ; Bertolazzi Zocca, Vitoria Fernanda ^[3] ; de Paiva, Gabriela Barbosa ^[3] ; Ferreira, Henrique ^[4] ; Pedrolli, Danielle Biscaro ^[3] ; Bertolini, Maria Celia ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Paulista, Dept Bioquim & Tecnol Quim, Inst Quim, UNESP, BR-14800900 Araraquara, SP - Brazil

^[2] Univ Calif Riverside, Dept Biochem, Riverside, CA 92521 - USA

^[3] Univ Estadual Paulista, Dept Bioproc & Biotecnol, Fac Ciencias Farmaceut, UNESP, BR-14800903 Araraquara - Brazil

^[4] Univ Estadual Paulista, Dept Bioquim & Microbiol, Inst Biociencias, UNESP, BR-13506900 Rio Claro, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: MICROBIOLOGY-SGM; v. 165, n. 3, p. 355-365, MAR 2019.
• Citações Web of Science: 0

Resumo

Upstream open reading frames (ORFs) are frequently found in the 5'-flanking regions of genes and may have a regulatory role in gene expression. A small ORF (named cohL here) was identified upstream from the copAB copper operon in Xanthomonascitri subsp. citri (Xac). We previously demonstrated that copAB expression was induced by copper and that gene inactivation produced a mutant strain that was unable to grow in the presence of copper. Here, we address the role of cohL in copAB expression control. We demonstrate that cohL expression is induced by copper in a copAB-independent manner. Although cohL is transcribed, the CohL protein is either not expressed in vivo or is synthesized at undetectable levels. Inactivation of cohL (X. citri cohL polar mutant strain) leads to an inability to synthesize cohL and copAB transcripts and consequently the inability to grow in the presence of copper. Bioinformatic tools predicted a stem-loop structure for the cohL-copAB intergenic region and revealed that this region may arrange itself in a secondary structure. Using in vitro gene expression, we found out that the structured 5'-UTR mRNA of copAB is responsible for sequestering the ribosome-binding site that drives the translation of copA. However, copper alone was not able to release the sequence. Based on the results, we speculate that cohL plays a role as a regulatory RNA rather than as a protein-coding gene. (AU)

• Processo FAPESP: 05/04036-3 - Resistência a cobre em Xanthomonas axonopodis pv. citri: estudos funcionais de algumas proteínas relacionadas ao mecanismo
• Beneficiário: Maria Celia Bertolini
• Modalidade de apoio: Auxílio à Pesquisa - Regular