Comparison of gene expression during meiosis between wild-type and msh5-deficient strains of Coprinopsis cinerea

Meiosis was compared in msh5-22 and wild type strains of C. cinerea at 6 time points spanning the meiotic timecourse. Abstract: The basidiomycete Coprinopsis cinerea is well-suited to studies of meiosis because meiosis progresses synchronously in ten million cells within each mushroom cap. Approximately 20% of C. cinerea genes exhibit changing expression during meiosis, but meiosis and mushroom development happen concurrently so differentially expressed genes might not be directly involved in meiotic processes. Using microarrays, we examined global gene expression across a meiotic time course in two mutants in which meiosis arrests but mushrooms develop normally. Genes differentially expressed in the mutants compared to wild type are likely to be involved in meiosis and sporulation as opposed to mushroom development. In rad50-1, which arrests in late prophase, RNA abundance for a group of early meiotic genes remains high, while the expression of a group of late meiotic genes is never induced. In contrast, in msh5-22 (which fails to undergo pre-meiotic DNA replication), both early and late meiotic genes are underexpressed relative to wild type at late meiotic time points as the cells die. Genes that are differentially expressed in both mutants are particularly strong candidates for playing roles in meiosis and sporulation. Six time points were analyzed, with four biological replicate msh5-22 samples used for each timepoint. Reference wild-type samples consisted of pooled RNA from ten samples at the appropriate timepoint.