Alternative Processing of Growth Hormone Receptor Transcripts*

GH RECEPTOR (GHR) is a transmembrane protein that binds GH with high affinity and specificity. Expression of the receptor is a requirement for cellular responsiveness to GH. The primary transcript that generates the GHR mRNA can undergo alternative processing to produce several related mRNAs, including transcripts that encode the circulating GH-binding protein (GHBP) and a truncated GHR that inhibits normal cellular responses to GH in vitro. In addition, the use of alternative promoters and transcription start sites in the GHR gene-regulatory region generates transcript forms that differ only in the 5′-untranslated region (5′-UTR). This article will review the transcripts originating from the GHR gene. The introduction will address the expression of GHR and GHBP, the major transcripts of the gene. The second section describes the structure of the GHR gene. The third section describes the types of alternative transcripts produced by the gene, the alternative processing mechanisms that produce them, and the biological functions of their protein products. The final section suggests future studies on the expression and function of alternative GHR transcripts.