In vitro binding of cattle PstI SINE with a 33-kDa nuclear protein

A PstI family of SINEs (short interspersed elements) has been identified in some of the members of the family Bovidae, for example, cattle, buffalo an d goat. In vitro DNA-protein interactions were studied to provide a better understanding of the function of these SINEs in the genome. Use of one such cattle PstI interspersed repeat sequence, as a probe in gel retardation as says, has lead to the identification of a repeat DNA-binding factor PIRBP ( PstI interspersed repeat binding protein) from cattle liver nuclear extract . Southwestern analysis with liver nuclear extracts from cattle, goat, and buffalo revealed the presence of a PIRBP-like nuclear factor in all three s pecies belonging to the family Bovidae. Deletion analysis localized the PIR BP binding site to an 80-bp (337-417bp) region within the cattle PstI seque nce. UV crosslinking and Southwestern analyses clearly indicated that PIRBP is a singular, small polypeptide of 33-kDa molecular mass. Homology search of the nucleic acids database revealed that the cattle PstI sequence was a ssociated with many different genes of the family Bovidae, either in the 5' flanking region, 5' locus activating region, 3' UTR or in intervening sequ ences. The binding of the cattle PstI SINE by PIRBP and its association wit h the regulatory regions of the genes suggests that it plays an important r ole in the bovine genome.