Transcription factors of alphaherpesviruses not only control the expression of their own viral genes, but also influence the gene expression of mammalian cells. In the course of breeding of the transgenic mouse line (TgIE96) expressing the immediate-early protein IE180 of pseudorabies virus belonging to the subfamily Alphaherpesvirinae, we found that TgIE96 male mice suffered from severe breeding difficulties. Testes of TgIE96 were smaller than that of non-transgenic littermates and abnormal spermatogenesis such as morphological, numerical and functional anomalies of spermatozoa were found in the transgenic mouse line. Expression of IE180 was detected in the germ cells at all stages, especially spermatocytes, and fewer Sertoli cells. In addition, expression of IE180 was also detected in the germinal cells of C57BL/6 mice inoculated with PRV into their testes. These results suggest that IE180 of PRV induces male infertility by abnormal spermatogenesis, which effect morphological, numerical, and functional anomalies of spermatozoa, in transgenic mice. (C) 2013 Elsevier Inc. All rights reserved.