Gene age shapes the transcriptional landscape of sexual morphogenesis in mushroom forming fungi (Agaricomycetes)

Multicellularity has been one of the most important innovations in the history of life. The role of regulatory evolution in driving transitions to multicellularity is being increasingly recognized; however, patterns and drivers of transcriptome evolution are poorly known in many clades. We here reveal that allele-specific expression, natural antisense transcripts and developmental gene expression, but not RNA editing or a developmental hourglass act in concert to shape the transcriptome of complex multicellular fruiting bodies of fungi. We find that transcriptional patterns of genes are strongly predicted by their evolutionary age. Young genes showed more expression variation both in time and space, possibly because of weaker evolutionary constraint, calling for partially non-adaptive interpretations of evolutionary changes in the transcriptome of multicellular fungi. Gene age also correlated with function, allowing us to separate fruiting body gene expression related to simple sexual development from that potentially underlying complex morphogenesis. Our study highlighted a transcriptional complexity that provides multiple speeds for transcriptome evolution, but also that constraints associated with gene age shape transcriptomic patterns during transitions to complex multicellularity in fungi.Competing Interest StatementThe authors have declared no competing interest

Lessons on fruiting body morphogenesis from genomes and transcriptomes of Agaricomycetes.

Fruiting bodies (sporocarps, sporophores or basidiomata) of mushroom-forming fungi ( Agaricomycetes) are among the most complex structures produced by fungi. Unlike vegetative hyphae, fruiting bodies grow determinately and follow a genetically encoded developmental program that orchestrates their growth, tissue differentiation and sexual sporulation. In spite of more than a century of research, our understanding of the molecular details of fruiting body morphogenesis is still limited and a general synthesis on the genetics of this complex process is lacking. In this paper, we aim at a comprehensive identification of conserved genes related to fruiting body morphogenesis and distil novel functional hypotheses for functionally poorly characterised ones. As a result of this analysis, we report 921 conserved developmentally expressed gene families, only a few dozens of which have previously been reported to be involved in fruiting body development. Based on literature data, conserved expression patterns and functional annotations, we provide hypotheses on the potential role of these gene families in fruiting body development, yielding the most complete description of molecular processes in fruiting body morphogenesis to date. We discuss genes related to the initiation of fruiting, differentiation, growth, cell surface and cell wall, defence, transcriptional regulation as well as signal transduction. Based on these data we derive a general model of fruiting body development, which includes an early, proliferative phase that is mostly concerned with laying out the mushroom body plan (via cell division and differentiation), and a second phase of growth via cell expansion as well as meiotic events and sporulation. Altogether, our discussions cover 1 480 genes of Coprinopsis cinerea, and their orthologs in Agaricus bisporus, Cyclocybe aegerita, Armillaria ostoyae, Auriculariopsis ampla, Laccaria bicolor, Lentinula edodes, Lentinus tigrinus, Mycena kentingensis, Phanerochaete chrysosporium, Pleurotus ostreatus, and Schizophyllum commune, providing functional hypotheses for ~10 % of genes in the genomes of these species. Although experimental evidence for the role of these genes will need to be established in the future, our data provide a roadmap for guiding functional analyses of fruiting related genes in the Agaricomycetes. We anticipate that the gene compendium presented here, combined with developments in functional genomics approaches will contribute to uncovering the genetic bases of one of the most spectacular multicellular developmental processes in fungi. Citation: Nagy LG, Vonk PJ, Künzler M, Földi C, Virágh M, Ohm RA, Hennicke F, Bálint B, Csernetics Á, Hegedüs B, Hou Z, Liu XB, Nan S, M. Pareek M, Sahu N, Szathmári B, Varga T, Wu W, Yang X, Merényi Z (2023). Lessons on fruiting body morphogenesis from genomes and transcriptomes of Agaricomycetes. Studies in Mycology 104: 1-85. doi: 10.3114/sim.2022.104.01

Cutaneous lymphatic amyloid deposits in 'Hungarian-type' familial transthyretin amyloidosis: a case report

Multiple transthyretin (TTR) mutations have recently been identified and implicated in the development of familial systemic amyloidoses, but early diagnosis of these disorders is still largely unresolved. We investigated the presence and tissue distribution of TTR-derived amyloid in skin biopsies of a 59-year-old woman carrying the 'Hungarian-type' mutation of TTR (Asp18Gly). Clinical symptoms involved severe central nervous system dysfunction without signs of polyneuropathy, also referred to as the 'central form' of TTR-related systemic amyloidosis. Skin biopsy was also evaluated as a tool in order to diagnose this type of TTR amyloidosis. Biopsy samples were collected from the infra-axillary region. Light microscopy using Congo red and polarized light was used to diagnose amyloid deposits. Subsequently, electron microscopic analysis was performed to correlate the amyloid deposits with vicinal dermal structures. The amyloid class was determined by means of immunocytochemistry. TTR amyloid was primarily localized to lymphatic microvessels in the present case, whereas arterioles were devoid of TTR amyloid deposits. In addition, the well-known association of TTR amyloid with neural structures along the erector pilorum and around the sebaceous and serosal (sweat) glands was also evident. Electron microscopic analysis of amyloid deposits revealed characteristic amyloid fibrils that were irregular in shape, and exhibited a heterogeneous density and a random deposition pattern. Immunocytochemistry confirmed the cutaneous accumulation of TTR amyloid. In conclusion, amyloid deposits were abundantly present in the skin of a patient with 'Hungarian-type' TTR amyloidosis; skin biopsy seems to be appropriate for the diagnosis of this disorder. We showed that besides the erector pilorum, sweat glands and nerve terminals, lymphatic microvessels are also severely infiltrated by TTR amyloid. Whether these pathological alterations can exclusively be found in 'Hungarian-type' TTR amyloidosis should still be investigated. If such changes are not specific for the Asp18Gly mutation, they may be considered as diagnostic markers for 'central' TTR amyloid disorders.