J Clin Endocrinol Metab 2005 Dec 13;90(12):6596-602. Epub 2005 Sep 13.
Center for Research on Reproduction and Women's Health, University of Pennsylvania School of Medicine, Philadelphia 19104, USA.
Context: Polycystic ovary syndrome (PCOS) theca cells secrete increased levels of androgens. The mRNA and protein levels of the transcription factor GATA6, which regulates expression of several steroidogenic enzymes, are increased in PCOS theca cells. Thus, GATA6 is a PCOS candidate gene.
Objective: The objective of the study was to explore mechanisms by which GATA6 mRNA levels are increased in PCOS theca cells.
Design: Theca cell cDNA and genomic DNA from normal individuals and PCOS patients were subjected to quantitative RT-PCR and sequence analysis, respectively.
Setting: The experiments were performed in a university laboratory.
Participants: Four hundred sixty-nine families that contain at least one PCOS patient were ascertained for genetic studies. Theca cells were obtained from four normal individuals and four PCOS patients.
Results: Nascent GATA6 transcript levels, which reflect GATA6 gene transcription, were significantly increased in PCOS theca cells. In normal theca cells, GATA6 mRNA has a short half-life, which was attributed to an AU-rich 3'-untranslated region sequence. The half-life of GATA6 transcripts was also significantly longer in the PCOS theca cells. However, no sequence variations in the GATA6 gene locus were associated with PCOS.
Conclusions: In PCOS theca cells, GATA6 gene transcription and the stability of the GATA6 mRNA are increased. Because there is no sequence variation in the GATA6 gene locus, which is associated with PCOS, it is likely that the increased gene transcription and mRNA stability are due to intrinsic differences in PCOS theca cells.