A fruiting body-specific novel cDNA, mfbBc, containing continuous 5'-CCA(A/C)CA direct repeats within the coding region, derived from the basidiomycete Lentinula edodes

Screening for cDNA(s) homologous to Leras cDNA (Hori et al. 1991. Gene 105:91–96.) in the basidiomycete Lentinula edodes resulted in the isolation of a cDNA (designated mfbBc) encoding 394 amino acids, in place of isolation of a second ras cDNA. The mfbB gene showed developmental regulation, with mature fruiting bodies having much higher levels of mfbB transcript. Preprimordial mycelia and primordia contained low levels of mfbB transcript, mfbBc was found to contain eight continuous 5’-CCA(A/C)CA direct repeats and a 5’-CCACCG sequence in the proximity of the 5’ end on the coding strand. When cloned into a plasmid and propagated in Escherichia coil, the CA/TG direct repeats region was shown to decrease the superhelical density of the plasmid, suggesting the formation of an altered DNA structure.