Three yeast genes, PIR1, PIR2 and PIR3, containing internal tandem repeats, are related to each other, and PIR1 and PIR2 are required for tolerance to heat shock.
Toh-e A, Yasunaga S, Nisogi H, Tanaka K, Oguchi T, Matsui Y. Yeast. 1993 May; 9(5):481-94.