The nuclear matrix bound DNA fraction of rat testis showed enrichment in repetitive sequences found in the 450 bp band after gel electrophoresis of the Mspl digested rat DNA. DNA fragments isolated from this band were cloned. DNA of the clone pMspI8 showed homology to some representatives of rat LINE sequence family, and complcxcd in vitro more efficiently with testes nuclear matrix proteins than with yeast ARS1 sequence containing the matrix association region (MAR) or DNA from an other clone, MspI19. Western blot analysis showed that MspI8 sequence interacts with testes matrix protein of about 120 kDa.