Okuda, Yoshihiro, Daisuke Sasaki, Satoru Nogami, Yoshinobu Kaneko, Yoshikazu Ohya, and Yasuhiro Anraku. “Occurrence, horizontal transfer and degeneration of VDE intein family in Saccharomycete yeasts.” Yeast 20, no. 7 (2003): 563-573.
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VDE is a homing endonuclease gene originally discovered as an intervening element in VMA1 s of Saccharomyces cerevisiae . There have been two independent subfamilies of VDE , one from S. cerevisiae strain X2180-1A and the other from Saccharomyces sp. DH1-1A in the host VMA1 gene, and they share the identity of 96.3%. In order to search the occurrence, intra/interspecies transfer and molecular degeneration of VDE , complete sequences of VMA1 in 10 strains of S. cerevisiae , eight species of saccharomycete yeasts, Candida glabrata and Kluyveromyces lactis were determined. We found that six of 10 S. cerevisiae strains contain VDE s 99.7–100% identical to that of the strain X2180-1A, one has no VDE , whereas the other three harbour VDE s 100% identical to that of the strain DH1-1A. S. carlsbergensis has two VMA1 s, one being 99.8% identical to that of the strain X2180-1A with VDE 100% identical to that of the strain DH1-1A and the other containing the same VMA1 in S. pastorianus with no VDE. This and other evidence indicates that intra/interspecies transmissions of VDE s have occurred among saccharomycete yeasts. Phylogenetic analyses of VMA1 and VDE suggest that the S. cerevisiae VDE s had branched earlier than other VDE s from an ancestral VDE and had invaded into the host loci as relatively late events. The two VDE s seemed to degenerate in individual host loci, retaining their splicing capacity intact. The degeneration of the endonuclease domains was distinct and, if compared, its apparent rate was much faster than that of the protein-splicing domains. The VMA1 gene sequences determined in this study have been deposited in the GenBank data library under the Accession Nos shown in Table 1. Copyright © 2003 John Wiley & Sons, Ltd.