Urease gene of Trichophyton rubrum var. raubitschekii

The recent description (in GenBank) of a urease-encoding gene from Trichophyton rubrum provides an opportunity to compare this species to the highly similar T. rubrum var. raubitschekii. Therefore, the corresponding genomic DNA was recovered from T. rubrum var. raubitschekii, and the sequence and expression were compared for this urease gene in urease-positive and -negative isolates of T. rubrum and T. rubrum var. raubitschekii. The sequence (2371 bp) of the T. rubrum var. raubitschekii urease gene revealed the presence of three exons. Except for a three-amino acid insertion, the predicted proteins were identical, but demonstrated protein identity of approximately 70% compared to an Arthroderma gypseum homolog. Reverse transcription polymerase chain reaction analysis revealed the presence of a corresponding transcript in both urease-positive T. rubrum var. raubitschekii isolates examined; the same analysis did not detect this transcript in urease-negative isolates of T. rubrum.