POU-domain proteins Pit-1 and Oct-1 interact to form a heteromeric complex and can cooperate to induce expression of the prolactin promoter.
Two members of the POU-domain family of transcriptional activators, Pit-1 and Oct-1, are coexpressed in cells of the anterior pituitary gland. We demonstrate that the pituitary-specific developmental regulator Pit-1 can bind as a heterodimer with the widely expressed 100-kD Oct-1 protein to critical tissue-specific cis-active elements in the rat prolactin gene. Pit-1 and Oct-1 can also associate, in the absence of DNA, via their POU domains. Coexpression of Pit-1 and Oct-1 in a heterologous cell type results in reproducible 2- to 2.5-fold synergistic transcriptional effects on genes under control of the native prolactin promoter or of a single Pit-1 response element. These results suggest that a combinatorial pattern of heterodimeric and homodimeric interactions between different members of the POU-domain gene family can result when members of this large family are coexpressed in cells of developing and established organ systems, potentially regulating differential developmental gene activation.
Voss
J W
JW
Howard Hughes Medical Institute, School of Medicine, University of California, San Diego, La Jolla 92093-0648.
Wilson
L
L
Rosenfeld
M G
MG
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002522:Chlorocebus aethiops; D004268:DNA-Binding Proteins / Q000235:genetics*; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D051863:Host Cell Factor C1; D007668:Kidney; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D050811:Octamer Transcription Factor-1; D010903:Pituitary Gland, Anterior; D011388:Prolactin / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011487:Protein Conformation; D050817:Transcription Factor Pit-1; D014157:Transcription Factors / Q000235:genetics*; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; D051863:Host Cell Factor C1; D046911:Macromolecular Substances; D050811:Octamer Transcription Factor-1; D050817:Transcription Factor Pit-1; D014157:Transcription Factors; D011388:Prolactin