The goal of this project is to identify key genes involved in the development, differentiation, and function of the urogenital system (testis, ovary, kidney). Recessive and dominant screens were performed and affected lineages were mapped to chromosomal regions using a panel of 768 SNPs. All mice are available to the general scientific community. To date, 15 lines of mutant mice have been established. Defects include hypogonadism (mild to severe), germ cell loss, cryptorchidism, cystic kidneys and double ureter.

DAX1 is an X-linked orphan nuclear receptor that is mutated in patients that exhibit adrenal crisis and hypogonadism. In addition to identifying over 20 human DAX1 mutations, our laboratory has created a mouse knockout model of Dax1. Studies of these mice have identified a role for Dax1 in testicular steroidogenesis, gonadal development and, most strikingly, sex determination. Breeding of the Dax1 null mutant onto specific mouse strains causes male to female sex reversal (XY females). Current experiments are focused on identifying the molecular and cellular pathways through which Dax1 acts in the developing and adult gonad (testis and ovary). Projects include crossing of Dax1 null mice with other genetic strains that exhibit gonadal defects and in vitro experiments to identify new Dax1 protein interacting partners directly. The image shows the developing gonad in a WT male, a WT female and a Dax1 null male at embryonic day 13.5.

Park SY, Meeks J, Raverot G, Pfaff LE, Weiss J, Hammer GD, Jameson JL. Nuclear receptors Sf1 and Dax1 function cooperatively to mediate somatic cell differentiation during testis development. Development. 2005 May;132(10):2415-23.

Meeks JJ, Weiss J, Jameson JL. Dax1 is required for testis determination. Nat Genet 2003 34:32-33.

Yu RN, Ito M, Saunders TL, Camper SA, Jameson JL. Role of Ahch in gonadal development and gametogenesis. Nat Genet 1998; 20: 353-357.

Spermatogenesis is a complex process involving sequential mitotic and meiotic divisions to produce mature sperm. This process begins with the spermatogonial stem cells (SSCs), which divide and undergo a cell fate decision to either self-renew the stem cell population or to begin the process of differentiation. Sox3 is a transcription factor noted for it’s evolutionary relationship to the male-determining gene, Sry. Experiments in our laboratory demonstrated that Sox3 is expressed in the type A population of spermatogonia, which includes the SSCs. To further understand the role of Sox3 in spermatogenesis, we deleted this gene in mice. Sox3 null male mice are hypogonadal, with severe defects in spermatogenesis and consequent infertility. Additional studies suggest that expression of several early SSC markers is dependent on the presence of Sox3. Current studies in the laboratory are directed toward understanding the role of Sox3 in maintenance of the SSC pool. The image shows expression of Sox3 (red) at the base of 2 normal seminiferous tubules. Note the lack of Sox3 expression in differentiating germ cells (green).

Raverot G, Weiss J , Park S , Hurley L, Jameson JL. Sox3 expression in undifferentiated spermatogonia is required for the progression of spermatogenesis. Dev Biol. 2005 Jul 1;283(1):215-25.

Weiss J, Meeks JJ, Hurley L, Raverot G, Frassetto A, Jameson JL. Sox3 is Required For Gonadal Function, But Not Sex Determination, in Males and Females. Mol Cell Biol 2003 23:8084-91

It is well-established that estrogen alters the function of multiple body systems, including the reproductive, endocrine & cardiovascular systems, the skeleton, and behavior. Less well-understood are the cellular mechanisms through which ER acts. Two major advances in the field were the identification of a second estrogen receptor, ERβ, and the recognition that at least the first identified ER, now called ERα, can signal through pathways that do not involve binding to the “classical” estrogen response element (ERE) in DNA. This latter mode of signaling, the “non-classical” pathways, are of particular interest to our laboratory. We have conducted extensive experiments to understand the role of the non-classical pathways in the reproductive tissues. Past projects include mutagenesis and biochemical/molecular analysis to create a mutant ERα that distinguishes classical from non-classical signaling, and expression profiling using adenoviral gene transfer to create cellular models of isolated non-classical ERα signaling. One of our current projects is focused on determining the transcriptional complexes present on the promoters of ERα target genes. We have also created a knock-in model (NERKI) to isolate non-classical ERα signaling in vivo. Ongoing studies examine a number of estrogen target tissues, including the breast, ovary, uterus and neuroendocrine hypothalamus. The image illustrates substantial rescue of the hemorrhagic phenotype in NERKI animals (right) compared to ER knockout animals (center). A WT ovary is pictured at left.

Glidewell-Kenney C, Hurley LA, Pfaff L, Weiss J, Levine JE, Jameson JL. Nonclassical estrogen receptor a signaling mediates negative feedback in the female mouse reproductive axis. Proc Natl Acad Sci USA 2007 104:8173-77.

O'Brien JE, Peterson TJ, Tong MH, Lee EJ, Pfaff LE, Hewitt SC, Korach KS, Weiss J, Jameson JL.
Estrogen-induced Proliferation of Uterine Epithelial Cells Is Independent of Estrogen Receptor alpha Binding to Classical Estrogen Response Elements. J Biol Chem. 2006 281:26683-92.

Jakacka M, Ito M, Martinson F, Ishikawa T, Lee EJ, Jameson JL. An estrogen receptor (ER)alpha deoxyribonucleic acid-binding domain knock-in mutation provides evidence for nonclassical ER pathway signaling in vivo. Mol Endocrinol 2002 16:2188-201.

Disorders of reproduction and metabolism represent a significant social, medical, and economic burden for individuals and society. For example, approximately 1 in 10 couples in the United States are infertile and an additional 10% of adults in this country have abnormal levels of thyroid hormone. In all cases, a subset of these patients is likely to have an underlying genetic disorder that is either inherited (germline) or acquired (somatic). Over the past decade, many genes have been identified that influence the development and function of the hypothalamus and pituitary as well as their target organs, which includes the gonads, thyroid gland, adrenal gland and many others. These genes encode an array of transcription factors, matrix proteins, hormones, receptors, and enzymes that are expressed at multiple levels of the hypothalamo/pituitary/end-organ axis, and regulate the complex developmental, paracrine, and endocrine interactions that are necessary for reproduction and metabolism. Nonetheless, most heritable cases of endocrine and metabolic disease remain idiopathic.

Identifying naturally occurring genetic mutations provides unique insight into the role that these factors play in the human. In addition, defining the genetic basis of disease has significant benefits for the patients, as appropriate and educated counseling can be provided and treatment tailored to the individual. Our laboratory has been identifying genetic mutations in patients for over 2 decades. Some of the genes in which we have identified human disease-causing defects are luteinizing hormone (LH), thyroid hormone receptor (TR), DAX1 (see above), steroidogenic factor 1 (SF1), follicle-stimulating hormone (FSH), FSH receptor (FSHR), Kallmans (KAL1) and steroidogenic acute regulatory protein (StAR). The image illustrates a heterozygous mutation (green residue) we identified in the “P-box” of SF-1 in a patient with complete 46XY sex-reversal, primary adrenal failure and persistent Mϋllerian structures.

Ozisik G, Mantovani G, Achermann JC, Persani L, Spada A, Weiss J, Beck-Peccoz P, Jameson JL. An Alternate Translation Initiation Site Circumvents an Amino-Terminal DAX1 Nonsense Mutation Leading to a Mild Form of X-Linked Adrenal Hypoplasia Congenita. J Clin Endocrinol Metab 2003 88:417.

Achermann JC, Ito M, Ito M, Hindmarsh PC, Jameson JL. A mutation in gene encoding steroidogenic factor-1 causes XY sex-reversal and adrenal failure in humans. Nat Genet 1999; 22:125-126.

Weiss J, Axelrod L, Whitcomb RW, Harris PE, Crowley WF, Jameson JL. Hypogonadism caused by a single amino acid substitution in the beta subunit of luteinizing hormone. N Engl J Med. 1992 326:179-83.