Yves Lachance

Assignment of the human 3β-hydroxysteroid dehydrogenase gene (HSDB3) to the p13 band of chromosome 1

Three-beta-hydroxysteroid dehydrogenase (HSDB3) is the enzyme which catalyses the oxidative conversion of delta 5-3 beta-hydroxy steroids to the delta 4-3-keto configuration and is therefore involved in the biosynthesis of all classes of hormonal steroids, namely progesterone, glucocorticoids, mineralocorticoids, androgens, and estrogens. Deficiency of the enzyme is associated with congenital adrenal hyperplasia and is usually lethal in early life. Despite its crucial role, chromosome assignment of the gene for this enzyme has not been reported. Using in situ hybridization, we report that hybridization with labeled human HSDB3-specific cDNA yielded 27% of silver grains associated with chromosome 1 with a maximal concentration in the p13 band.

Purification, Cloning, Complementary DNA Structure, and Predicted Amino Acid Sequence of Human Estradiol 17β‐Dehydrogenase

Seventeen-P-hydroxysteroid dehydrogenase ( 17P-HSD) is the enzyme that catalyzes the interconversion of dehydroepiandrosterone (DHEA) and Sandrostenediol, 4-androstenedione and testosterone, and estrone and estradiol. This enzyme is present in many tissues such as the placenta,’,? testis,3 kidney,4 liver,’ skin? and ovary.’ This enzyme is likely to play a key role in the regulation of intracellular concentrations of sex hormones. The androgen testosterone and the estrogen 17Pestradiol are known to play an essential role in the development, growth, and function of all tissues responsible for reproduction and fertility in men and women. Moreover, sex steroids are involved in the regulation of hormone-sensitive cancer growth, especially prostate,* b r e a ~ t , ~ and endometrial cancer.IO Despite its purification from many tissues”-I4 and its partial biochemical chara c t e r i ~ a t i o n , ~ ~ ’ ~ little was known about the structure of this enzyme. We report the purification, cloning, and deduced amino acid sequence of estradiol 17pdehydrogenase (E2DH) from human placenta. The availability of cDNAs for EzDH offers the opportunity of studying in detail the factors controlling the expression of this crucial enzyme not only in gonadal but also in several peripheral estrogen target tissues.

Isolation and Sequence of the Human Glucocorticoid Receptor Gene Promoter. Cloning of the Human Androgen Receptor cDNA

We have isolated the promoter region of the human glucocorticoid receptor (hGR) gene from the λEMBL-3 human genomic library using synthetic oligonucleotides corresponding to the 5’ end of hGR cDNA. The clone was fine mapped by restriction digestion, hybridization with hGR cDNA probes and by DNA sequence analysis and found to contain an open reading frame corresponding to the hGR cDNA from amino acids 1–131 separated by a large intron from the 5’ noncoding sequences. The promoter region of the hGR has been identified by primer extension, nuclease S1 mapping using hGR mRNA from human prostatic carcinoma cells (LNCaP) and human breast tumor cells (MCF-7), by in vitro transcription using hGR-DNA fragments as template and by DNA sequence analysis. The sequence of the hGR promoter reveals that it contains neither a “TATA box” nor a “CART box” and has an extremely high “G+C” content. Gene transfer studies with hGR-CAT chimeric plasmids into COS-cells showed that the hormonal regulatory sequences of hGR is contained within a 4 kb EcoRl-XbaI fragment.