Coprinopsis cinerea is a species of mushroom in the family Psathyrellaceae. Commonly known as the gray shag, it is edible, but must be used promptly after collecting. Coprinopsis cinerea is an important model organism for studying fungal sex and mating types, mushroom development, and the evolution of multicellularity of fungi. The genome sequence was published in 2010. It is considered to be particularly suited organism to study meiosis, due to its synchronous meiotic development and prolonged prophase. Research Antibiotics Researchers in 2014 discovered a protein produced by Coprinopsis cinerea with antibiotic properties. The protein, known as copsin, has similar effects to other non-protein organically derived antibiotics. To date, it has not been determined whether antibiotic medicine for humans and other animals can be developed from this protein. Culturing Coprinopsis cinerea can be grown on complex (e.g. YMG, YMG/T) or minimal media (e.g. mKjalke medium), solid or liquid, with or without agitation, at 25 °C or optimally at 37 °C. It can be grown in dark or with 12-h light/12-h dark cycle. Strains C. cinereus strain PG78 (A6B42, trp1.1;1.6, pab1) is an AmutBmut monokaryon, self-compatible strain, with trp- and pab-auxotrophic markers (requires tryptophan and p-aminobenzoate). Genome Coprinopsis cinerea strain Okayama 7 (#130) was sequenced with 10x coverage in 2003. A third and most recent revision of the sequence of strain Okayama 7 (#130) was released in 2010. Its haploid genome is ca. 37.5 Mb. Molecular cloning Coprinopsis cinerea can be transformed with exogenous DNA by transformation when the fungus is a protoplast. It was found that disrupting (knockout or RNAi silencing) ku70 homologue can increase gene targeting via increased homologous recombination. Either protoplasts derived from oidia or vegetative mycelium can be used, however, gene targeting was found to be higher by 2% (based on phenotyping) when using vegetative mycelium. Otherwise, insertion of integrative vectors ectopically and with small homologous regions can be used, likely with low transformation efficiency. Earlier, REMI (restriction enzyme-mediated integration) could be used to insert exogenous DNA into the chromosome to produce mutant strains. This relies on inserting exogenous DNA and restriction enzymes into the protoplast cell, allowing for the enzymes to cut the chromosome at specific sites which match those sites used to produce linearized plasmid DNA with the gene of interest; subsequently, host enzymes ligate the cut sites and thus produce integrated heterologous, exogenous DNA. Although successful, undesirable mutations are likely. Chemical mutagenesis (also random) can