Expression and binding properties of two isoforms of the human growth hormone receptor.
Two isoforms of the human growth hormone receptor mRNA, one containing exon 3 (encoding an extracellular domain of the receptor), hGHR, and one excluding exon 3, hGHRd3, have been described. To study the cellular distribution of the two types of messengers we have analysed a panel of tissues. Both isoforms were expressed independently or simultaneously depending on the tissue studied. To investigate the binding properties of hGHRd3 we have cloned its cDNA in a eukaryotic expression vector; transient expression in COS-7 cells showed that the receptor without exon 3 was expressed on the plasma membrane and was able to bind human growth hormone (hGH) with the same high affinity as hGHR. Human lactogen (hCS) removed 125I-hGH bound to the full-length and exon 3-excluding receptors to the same extent. These results show that hGHR and hGHRd3 have tissue-specific expression and share identical binding properties for hGH and hCS and leave open the possibility that exon 3 might influence receptor signalling.
Sobrier
M L
ML
Laboratoire de Génétique Moléculaire, Institut National de la Santé et de la Recherche Médicale U.91, Hôpital Henri Mondor, Créteil, France.
Duquesnoy
P
P
Duriez
B
B
Amselem
S
S
Goossens
M
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D005091:Exons; D015870:Gene Expression; D013006:Growth Hormone / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D010928:Placental Lactogen / Q000378:metabolism; D012326:RNA Splicing; D012333:RNA, Messenger / Q000032:analysis / Q000737:chemistry; D011986:Receptors, Somatotropin / Q000235:genetics* / Q000378:metabolism*; D014018:Tissue Distribution; D014162:Transfection
D012333:RNA, Messenger; D011986:Receptors, Somatotropin; D013006:Growth Hormone; D004247:DNA; D010928:Placental Lactogen