Nucleotide Sequence Analysis of the 5S Ribosomal RNA Gene of the Mushroom Tricholoma matsutake

From a cluster of structural rRNA genes which has previously been cloned (Hwang and Kim, in submiddion; J. Microbiol Biotechnol.), a 1.0-kb EcoRI fragment of DNA which shows significant homology to the 25S and 5S rRNAs of Tricholoma matsutake was used for sequence analysis. Nucleotide sequence was biditectionally determined using deletion series of the DNA fragment. Comparing the resultant 1016-base sequence with sequences in the database, both the 3í end of 25S rRNA gene and 5S rRNA gene were searched. The 5S rRNA gene is 118-bp in length and is located 158-bp downstream of 3í end of the 25S rRNA gene. IGS1 and IGS2 (partial) sequences are also contained in the fragment. Multiple alignment of the 5S rRNA sequences was carried out with 5S rRNA sequences from some members of the subdivision Basidiomycotinaobtained from the database. Phylogenetic analysis with distance matrix established by Kimura's 2-paramer method and phylogenetic tree by UPGMA method proposed that T. matsutake is closely related to Efibulobasidium albescens. Secondary structure of 5S rRNA was also hypothesized to show similar topology with its generally accepted eukaryotic counterpart.