THE PITUITARY TRANSCRIPTION FACTOR GHF-1 PIT-1 - AN EVOLUTIONARY OVERVIEW/

Growth hormone (GH) transcription factor 1 (GHF-1) or pituitary transc ription factor 1 (Pit-1) is a pituitary gland-specific homeodomain pro tein of the POU subclass. POU proteins exert critical developmental an d transcriptional functions. Two functional regions, the DNA-binding o r POU domain and the transcriptional serine-threonine activation domai n (STA) are highly conserved between fishes and primates. However, a v ariability in the length of the STA domain (between 71 and 128 amino a cid residues) is found in different species as well as isoforms genera ted by alternative splicing.