Pre-translational regulation of luteinizing hormone receptor in follicular somatic cells of cattle.
Differential regulation of LHR in theca cells (TC) and granulosa cells (GC) is important for normal follicular development. Unlike TC, GC only acquire LH-responsiveness during the later stages of antral follicle development. This study tested the hypothesis that differential LH-responsiveness in these two cell types may be due, in part, to shifts in cellular patterns of alternatively spliced LHR mRNA transcripts which may not be obvious from analysis of total LHR gene expression. It also further explored the role of translation inhibition by an LHR binding protein (LHBP), normally associated with the production of endogenous cholesterol. LHR mRNA variation arises as a result of the alternative splicing of two variable deletion sites (VDS) designated 5' VDS and 3' VDS, and it was proposed that differences in cell sensitivity to LH may be due in part to variations in the pattern of the mRNA expression of the receptor variants. The outcomes of the present study support a dynamic multi-facetted regulation of LHR during pre-translation. Not only did the ratio between variants change during antral follicle growth and in vitro cell differentiation but also between TC and GC. Regulation could also be linked to LH concentration feedback mechanisms as the absence of LH caused cultured TC to markedly up-regulate amounts of LHR mRNA. In both TC and GC, LHR mRNA was greatly reduced after treatment to block mevalonate production in the de novo cholesterol pathway, adding further support for a regulatory mechanism linked to enriched cellular amounts of mevalonate kinase.
University of Nottingham, Division of Child Health, Obstetrics and Gynaecology, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom. Electronic address: peter.marsters@nottingham.ac.uk.
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P
Marsters
School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Sutton Bonington, Leicestershire LE12 5RD, United Kingdom.
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NR
Kendall
University of Nottingham, Division of Child Health, Obstetrics and Gynaecology, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom.
B K
BK
Campbell
D000818:Animals; D002417:Cattle / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D006107:Granulosa Cells / Q000378:metabolism*; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D008148:Lovastatin / Q000031:analogs & derivatives / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011974:Receptors, LH / Q000235:genetics / Q000378:metabolism*; D013799:Theca Cells / Q000378:metabolism*
D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D020033:Protein Isoforms; D012333:RNA, Messenger; D011974:Receptors, LH; C012258:mevastatin; D007986:Luteinizing Hormone; D008148:Lovastatin
Follicle; Granulosa cells; Luteinizing hormone receptor; Pre-translational regulation; Theca cells; Variable deletion site