Biochemical and genetic characterization of the porcine Prophet of Pit-1 pituitary transcription factor

Prophet of Pit-1 (Prop-1) is a paired class homeodomain transcription facto r that is specifically expressed in the pituitary gland. Mutations in the P rop-1 gene cause compound pituitary diseases in mouse models and human pati ents. We have cloned and analyzed the porcine ortholog of Prop-1. Analysis of cDNAs revealed that the porcine Prop-1 secluence is similar to the mouse and human proteins within the homeodomain and carboxyl terminus, but the a mino terminus is poorly conserved. The Prop-1 gene consists of three exons and two introns and spans 3.8 kilobases of genomic DNA. In addition, we map ped Prop-1 to the q arm of pig chromosome two. During development, Prop-1 i s expressed at the time of pituitary organogenesis. In the adult, expressio n was observed at low levels only in the pituitary gland. The porcine Prop- 1 protein displays similar biochemical, DNA binding, and transcriptional ac tivities to human PROP-1. We conclude that, although the structural diverge nce between the porcine and human PROP-1 molecules may indicate some distin ct functions, the porcine Prop-1 gene encodes a pituitary transcription fac tor with similar overall activities to the human ortholog. (C) 2000 Elsevie r Science Ireland Ltd. All rights reserved.