Horm Metab Res 2009; 41(1): 30-34
DOI: 10.1055/s-0028-1087174
Original Basic

© Georg Thieme Verlag KG Stuttgart · New York

DAX-1A (NR0B1A) Expression Levels are Extremely Low Compared to DAX-1 (NR0B1) in Human Steroidogenic Tissues

Y. Nakamura 1 , 2 , C. Vargas Morris 1 , H. Sasano 2 , W. E. Rainey 1
  • 1Department of Physiology, Medical College of Georgia, Augusta, Georgia, USA
  • 2Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Japan
Further Information

Publication History

received 14.04.2008

accepted 01.07.2008

Publication Date:
25 September 2008 (online)

Abstract

The orphan nuclear receptor DAX-1 (dosage-sensitive sex reversal-AHC critical region on the X chromosome gene 1; NR0B1) is known for its role in human development, specifically sex determination and steroidogenesis. Several recent publications have described an alternatively spliced form of DAX-1 called DAX-1A (NR0B1A). DAX-1A is encoded by exons 1 and 2A of DAX-1, with exon 2A located within the DAX-1 intron 1. DAX-1A expression has been observed in several tissues, including adrenal gland, ovary, and testis. Transfection studies have further shown that DAX-1A has an inhibitory effect on DAX-1, suggesting a role for DAX-1A in the regulation of adrenal and gonadal differentiation/function. However, the relative level of DAX-1 versus DAX-1A transcripts still remains unclear. Herein, we developed and performed quantitative real-time RT-PCR to measure DAX-1 and DAX-1A mRNA expression levels in H295R human adrenal carcinoma cell lines, human adult and fetal adrenal glands, corpus luteum, testis, whole pre- and postmenopausal ovaries, ovarian follicles, placenta, liver, and kidney. These mRNA expression levels were quantified using DAX-1 and DAX-1A standard curves. In addition, Western blotting analysis was performed to examine both DAX-1 and DAX-1A protein levels in H295R cells, adrenal glands, corpus luteum, and liver. Both DAX-1 and DAX-1A mRNA were detected in all samples of H295R cells, human fetal and adult adrenals, testis, ovary, ovarian follicles, and corpus luteum. However, DAX-1 mRNA levels were significantly higher (> 37-fold) than that seen for DAX-1A (p<0.01). DAX-1A mRNA expression levels were undetectable in human liver, placenta, and kidney. Western blotting analysis results demonstrated that DAX-1 protein was predominantly expressed in H295R cells, human adult adrenal, and corpus luteum. These results suggest that in comparison to DAX-1A, DAX-1 is, by far, the predominant mRNA isoform found in human adrenal glands and gonads.

References

Correspondence

W. E. Rainey, PhD 

Department of Physiology

Medical College of Georgia

1120 15th Street

Augusta

30912 Georgia

USA

Phone: +1/706/721 76 65

Fax: +1/706/721 83 60

Email: [email protected]