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Scientific Basis of Male Hypogonadism
Published in Anthony R. Mundy, John M. Fitzpatrick, David E. Neal, Nicholas J. R. George, The Scientific Basis of Urology, 2010
Thang S. Han, Pierre-Marc G. Bouloux
GnRH-producing neurons also appear to be affected by mutations and deletions of the DAX-1 gene (dosage-sensitive sex reversal, adrenal hypoplasia congenita critical region on the X chromosome gene 1). DAX-1 is located on Xp21 and expressed in the hypothalamus, pituitary, adrenal gland, gonads, and gonadal structures during fetal development. It encodes a 470 AA orphan receptor related to the steroid receptor family. It regulates expression of hormones involved in sexual differentiation. Mutations in the C-terminal end of DAX-1 lead to hypo-gonadotrophic hypogonadism as well as adrenal hypoplasia congenita (24).
Beckwith–Wiedemann Syndrome
Published in Dongyou Liu, Handbook of Tumor Syndromes, 2020
Jirat Chenbhanich, Sirisak Chanprasert, Wisit Cheungpasitporn
The KCNQ1/CDKN1C domain includes at least three important imprinted genes: two maternally coding genes, KCNQ1 and CDKN1C, and one paternally non-coding gene, KCNQ1OT1. KCNQ1 encodes a voltage-gated potassium channel, and its germline mutation implicates in various inherited cardiac arrhythmias such as familial atrial fibrillation and long QT syndrome, including autosomal dominant Romano–Ward syndrome and autosomal recessive Jervell and Lange–Nielsen syndrome. The mutant potassium channel does not appear to involve in the pathogenesis of BWS directly. However, the untranslated transcripts from KCNQ1 allele might indirectly play an undiscovered role in the imprinting process. CDKN1C encodes a cell cycle regulator that inhibits cell proliferation by interacting with cyclin/CDK complexes during the G1 phase of cell cycle. The germline loss-of-function mutation of CDKN1C is associated with an overgrowth syndrome, BWS, whereas its gain-of-function mutation results in growth-retardation syndromes including Silver−Russell syndrome and IMAGe (intrauterine growth retardation, metaphyseal dysplasia, adrenal hypoplasia congenita, and genital anomalies) syndrome [12]. ICR2, in contrast to ICR1, is intragenic, locating within the 11th intron of the KCNQ1 gene, and contains the promotor of KCNQ1OT1 gene which encodes an antisense long non-coding RNA. ICR2 is not methylated in the paternal chromosome, and its KCNQ1OT1 transcript subsequently silences all the paternal imprinted genes within the domain, yet the mechanism by which long non-coding RNA silences imprinted genes is not fully understood. ICR2 is methylated on the maternal chromosome, resulting in the silencing of KCNQ1OT1 transcription and the expression of KCNQ1 and CDKN1C. Similar to ICR1, CTCF-binding sites have been identified in ICR2, and it has been postulated that the insulator model may contribute to the differential expression of the KCNQ1/CDKN1C domain as well [13].
Molecular cloning, characterization of dax1 gene and its response to progesterone in Misgurnus anguillicaudatus
Published in Drug and Chemical Toxicology, 2019
Weiran Huo, Ruyan Wan, Peijin Wang, Linxia Zhang, Xiaohua Xia
Environmental residues of P4 may alter hormone homeostasis and result in reproductive effects in humans and animals. Thus far, studies in fish have focused on the reproductive effects of P4 (DeQuattro et al., 2012, Blüthgen et al.2013a) at low concentrations. However, limited attention has been paid to the toxicologic effects of P4 on sex differentiation in fish. Until recently, several studies have reported that P4 could mainly alter the transcriptional levels of key genes involved in sex determination and differentiation (such as Amh, Dmrt1, Sox9a/b), and could contribute to disruption of sexual development and sex differentiation in zebrafish (Liang et al.2015, Svensson et al.2016). Therefore, it is necessary to assess and understand adverse effects of P4 on sex differentiation in fish.dax1, also called NR0B1 (the human nuclear receptor subfamily 0, group B, member 1), known as dosage-sensitive sex reversal, adrenal hypoplasia congenita (AHC) critical region on chromosome X, gene 1, is encoded by an X-linked gene that acts at multiple levels in the development of the hypothalamic–pituitary–adrenal (HPA) axis and hypothalamic–pituitary–gonadal (HPG) axis (Guo et al.1995, Ikeda et al.1996). The dax1 gene has a very simple genomic structure with two exons separated by a single intron, which is located in the same relative position across species (Zhang et al.2004). dax1 was initially described as an antitestis gene because its overexpression in male humans and mice causes male to female sex reversal (Ludbrook and Harley 2004, Ludbrook et al.2012, Rojek et al.2014). In fish, dax1 is involved in sex determination and in the regulation of embryonic development, neural differentiation and steroidogenesis in gonadal and adrenal tissues (Powers et al.2009, von Schalburg et al.2011, Haugen et al.2012, Chen et al.2016). To further investigate the evolution and functions of dax1 in male and female sex determination, the transcriptional expression levels of dax1 is investigated in the present study.