Tandem organization and highly disparate expression of the two laccase genes lcc1 and lcc2 in the cultivated mushroom Agaricus bisporus

Smith, M. A.; Shnyreva, A.V.; Wood, David А.; Thurston, Christopher F.

doi:10.1099/00221287-144-4-1063

Cited by 53 publications

(41 citation statements)

References 40 publications

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“…The existence of multiple genes encoding different laccase isoenzymes has been demonstrated in several fungi (Mansur et al, 1997;Smith et al, 1998;Giardina et al, 1999). Moreover, laccase gene expression depends on cultural conditions, and differentially regulated systems to control laccase production have been reported (Collins & Dobson, 1997;Mansur et al 1998;Muñoz et al;.…”

Section: Introductionmentioning

confidence: 99%

Metal-responsive elements in Pleurotus ostreatus laccase gene promoters

2003

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Fungal laccase gene transcription is strongly induced by copper ions; notably, some laccase promoters contain multiple putative metal-responsive elements (MREs). Previously, it has been demonstrated that the Pleurotus ostreatus laccase genes poxc and poxa1b are transcriptionally induced by copper, and several putative MREs were found in the promoter regions of these genes, which extend for about 400 nt upstream of the start codon (ATG). Identification of MRE sequences, which are protected by protein binding in the poxc and poxa1b promoter regions, has been achieved by footprinting analyses. Electromobility shift assays led to the evaluation of the ability of the identified MREs to bind protein(s), and the role of specific nucleotides of these elements in complex formation has also been analysed. The formation of complexes between analysed MREs and fungal proteins requires the absence of metal ions. Proteins extracted from fungus grown in copper-depleted medium are able to form complexes with MREs, whilst proteins extracted from fungus grown in copper-containing medium are able to form complexes only in the presence of a metal chelator. Moreover, copper-depleted proteins are unable to form complexes when copper or zinc ions are added. UV-cross-linking analyses led to the determination of the molecular masses of the MRE-binding proteins. In the poxa1b promoter, a GC-rich region, homologous to the core binding site for transcription factor Sp1, decreases the binding affinity of the adjacent MRE, affecting its interactions with fungal protein factors.

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Section: Introductionmentioning

confidence: 99%

Metal-responsive elements in Pleurotus ostreatus laccase gene promoters

2003

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“…Four different cDNA sequences have been found in Rhizoctonia solani (25), up to five laccase genes have been found in Trametes villosa (26,27), three genomic sequences have been found in the basidiomycete I-62 (14) and Pleurotus ostreatus (6)(7)(8), and two genes have been found in Agaricus bisporus (22). Thus, the biochemical diversity of laccase isoenzymes appears to be due to the multiplicity of laccase genes.…”

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confidence: 99%

Copper Induction of Laccase Isoenzymes in the Ligninolytic Fungus Pleurotus ostreatus

Palmieri

Giardina

Bianco

et al. 2000

Appl Environ Microbiol

464

303

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Pleurotus ostreatus is a white rot basidiomycete that produces several extracellular laccase isoenzymes, including phenol oxidase A1b (POXA1b), POXA2, and POXC. POXC was the most abundant isoenzyme produced under all of the growth conditions examined in this study. Copper was the most efficient inducer of laccase activity among the putative inducers tested. The amounts of all of the previously described laccase isoenzymes increased substantially in copper-supplemented cultures. Under these conditions expression of POX isoenzymes was regulated at the level of gene transcription. It is worth noting that poxa1b mRNA was the most abundant induced transcript at all of the growth times analyzed, and the amount of this mRNA increased until day 7. The discrepancy between the poxa1b transcript and protein amounts can be explained by the presence of a high level of the protein in P. ostreatus cellular extract, which indicated that the POXA1b isoenzyme could be inefficiently secreted and/or that its physiological activity could occur inside the cell or on the cell wall. Moreover, the POXA1b isoenzyme behaved uniquely, as its activity was maximal on the second day of growth and then decreased. An analysis performed with protease inhibitors revealed that the loss of extracellular POXA1b activity could have been due to the presence of specific proteases secreted into the copper-containing culture medium that affected the extracellular POXA1b isoenzyme.

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“…Antifungals such as monoterpenes evaporate when temperatures are moderately elevated, which makes the wood more accessible to fungi (Mattson et al 1988;Englund and Nussbaum 2000). Another possible reason for the increased CO 2 evolution is an up-regulation at the cellular level, as a response to heat shock, due to increased laccase production (Ritossa 1996;Smith et al 1998). Changes in carbon flux following forest fire (Kashian et al 2006) are important, since fire frequency on a global scale is predicted to increase (IPCC 2014).…”

Section: Discussionmentioning

confidence: 99%

Increased CO2 evolution caused by heat treatment in wood-decaying fungi

Carlsson

Jonsson

2017

Mycol Progress

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Wood-decaying fungi are regarded as the main decomposers of woody debris in boreal forests. Given that fungal respiration makes a significant contribution to terrestrial carbon flows, it is important to understand how the wooddecaying fungal metabolism is regulated in relation to different environmental conditions and disturbances. In the present study, we investigated the effect of temperature stress on wood decomposition rate in 18 species of wood-decaying fungi, representing a broad range of species-habitat associations. Heat shock duration and temperature were calibrated to match the conditions of a forest fire. We found a general increase in fungal decay rate after heat shock; the response was more pronounced in species associated with fire-prone forests. The underlying mechanism is unclear, but possibly relates to an up-regulation at the cellular level in response to heat shock. Our results show that the decomposition rate of dead wood can be strongly affected by environmental triggers.

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Tandem organization and highly disparate expression of the two laccase genes lcc1 and lcc2 in the cultivated mushroom Agaricus bisporus

Cited by 53 publications

References 40 publications

Metal-responsive elements in Pleurotus ostreatus laccase gene promoters

Metal-responsive elements in Pleurotus ostreatus laccase gene promoters

Copper Induction of Laccase Isoenzymes in the Ligninolytic Fungus Pleurotus ostreatus

Increased CO2 evolution caused by heat treatment in wood-decaying fungi

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