Nucleotide sequences of two PR-1 pseudogenes from Nicotiana tabacum cv. Wisconsin 38.

Two independent PR-1 X genomic clones (W38/1 and W38/3) were isolated from a tobacco (Nicotiana tabacum cv. Wisconsin 38) library. The clones are related to 2 other PR-I genes isolated from the tobacco cultivar Samsun NN. Clone W38/1 carries all structural features described for the PR-ld gene (1). Clone W38/3 is analogous to the PR-ca gene (2). However, several nucleotide changes do occur between the PR-at (-154 to 722) and W38/3 genes outside the PR-I coding region (at positions -154, -138, -125, -118, -79, -37, -1, 563 and 713, respectively). Both genes are pseudogenes carrying mutations within the highly conserved PR-I open reading frame. Lambda clone W38/1 contains a GAA where the UAA translation stop codon occurs in functional PR-I genes. Lambda clone W38/3 contains an ATC in place of the ATG translation initiation codon, a 2 bp insertion in the PR-I open reading frame at position 147, and 3 bp deletion at what would be the C-terminus of a putative encoded protein.