Identification of a hormonally regulated luteinizing hormone/human chorionic gonadotropin receptor mRNA binding protein. Increased mrna binding during receptor down-regulation.
To elucidate the molecular events associated with the regulation of luteinizing hormone/human chorionic gonadotropin (LH/hCG) receptor mRNA stability during hCG-induced receptor down-regulation, we have identified an LH/hCG receptor-specific mRNA binding protein. Proteins were isolated from control and down-regulated rat ovary and were incubated with in vitro transcribed RNAs corresponding to the full-length LH/hCG receptor, as well as 5'- and 3'-truncated receptor forms. Resultant ribonucleoprotein complexes were analyzed by RNA gel mobility shift. A prominent Mr 50,000 ribonucleoprotein complex was identified with the following characteristics: 1) specificity for LH/hCG receptor open reading frame sequences located between nucleotides 102 and 282; 2) lack of competition by nonspecific RNAs; 3) a 3-fold increase in RNA binding activity during hCG-induced receptor down-regulation; and 4) limited tissue expression. This report describes the first evidence of an LH/hCG receptor mRNA binding protein, which we term LRBP-1, for luteinizing hormone receptor RNA binding protein-1. This protein is a candidate for a trans-acting factor involved in the hormonal regulation of LH/hCG receptor mRNA stability in rat ovary.
Kash
J C
JC
Departments of Biological Chemistry and Obstetrics/Gynecology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0617, USA.
Menon
K M
KM
D000818:Animals; D001665:Binding Sites; D006063:Chorionic Gonadotropin / Q000378:metabolism; D015536:Down-Regulation; D005260:Female; D010053:Ovary / Q000378:metabolism; D011485:Protein Binding; D011555:Pseudopregnancy; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011974:Receptors, LH / Q000378:metabolism*
D006063:Chorionic Gonadotropin; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011974:Receptors, LH