In situ RNA-RNA hybridization: a useful method for analysis of the distribution of transcripts of various genes in Lentinula edodes fruiting bodies

Abstract

The in situ RNA-RNA hybridization was renewed understanding that it is a useful method for analysis of the distribution of transcripts of various genes in fruiting bodies of Lentinula edodes. By using this method, we obtained the following results. Large amounts of the transcripts of ribonucleotide reductase small subunit gene (Le.rnr2) and UMP-CMP kinase gene (uck1), which is a target of developmental regulator PRIB, are present in both hymenium and outer region of trama in the hymenophore (gill tissue). The hymenium is the part for production of basidiospores and the outer region of trama is the region branching out into subhymenium (on the top of which hymenium is formed). The Le.ras transcript is present mostly in outer region of trama and in trama cells, while the transcript of trimeric G-protein αsubunit gene (Le.ga1) is mostly in hymenium. The transcript of mfbC gene, which is the target of PRIB and probably encodes the protein interacting with a putative translation initiation factor 5A (eIF5A), is present in outer region of trama. The transcript of hyd1 (hydrophobin 1 gene), whose expressed product is considered to be involved in the formation in the extracellular matrix of lined air channels with a hydrophobic membrane, is present everywhere in the mycelial tissues of developing fruiting bodies except for the top parts of pileus (cap) and for prehymenophore. The region surrounding prehymenophore contains a high level of the transcript. These results suggest that Le.rnr2 and uck1 genes play a role mainly in the nucleotide biosynthesis essential for production of basidiospores and for divergence of trama cells into subhymenium cells. The Le.ras and mfbC play a role in divergence of mycelial cells and the Le.ga1 plays a role in spore-production. The hydrophobin-mediated air channels may be formed almost all the parts of developing fruiting bodies.