Differences between men and women, from physiological to molecular levels, occur in systems far more diverse than those primarily involved in reproduction. A known paradigm is the sex- specific pattern of gene expression in liver for a broad array of proteins that metabolize steroids and drugs, or function in pregnancy. These distinctions in expression are induced by the sex steroids acting via the pituitary to direct a specific profile of growth hormone secretion. Although studied mostly in rodents, this regulatory axis exists also in humans, where it may impact sex differences in drug sensitivity, incidence of certain liver diseases, or complications in pregnancy. Therefore, it is critical to ascertain mechanisms in such precise tissue-specific and hormonal control. An androgen-independent control in male-specific liver gene expression is revealed by mice carrying rsl alleles (regulator of sex-limitation). Rsl is involved in regulation of the mouse sex- limited protein (Slp) gene, which is normally restricted in expression to adult male liver and kidney. In mice homozygous for rsl, Slp also is expressed in females at puberty. Slp synthesis is also increased in the rsl males, and occurs even in rsl mice lacking androgen receptor, indicating that this regulation is independent of androgen induction. We have shown that the rsl effect is liver-specific and does not act on Slp in kidney, and that it affects the array of male-specific liver genes, including P450s and mouse urinary proteins (MUPs), to cause their expression in females. The rsl variant reveals that wild type Rsl's normal function enforces dimorphic liver gene expression by negative regulation that silences male-specific genes in females. A likely mechanism is via transcriptional repression that acts on Rsl target genes in both sexes, and is overcome in males by puberal hormonal induction. The overall goal of this project is to characterize this novel tissue- and gene-specific negative regulatory pathway and to identify the Rsl gene. We will: I) Clone the Rsl gene based on its chromosomal position, which is already narrowed to a genetic interval of 1.2 cM; II) Define the molecular basis of action by identifying Slp cis-acting elements that are targets of the Rsl pathway; III) Define temporal and spatial interaction between Rsl control and hormonal induction of the target genes. Establishing the basis of the Rsl pathway will enhance our understanding of basic mechanisms of gene expression. Further, Rsl control in mice may yield unique insights into regulation of liver genes in humans.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK053998-02
Application #
6178043
Study Section
Biochemical Endocrinology Study Section (BCE)
Program Officer
Serrano, Jose
Project Start
1999-09-01
Project End
2003-08-31
Budget Start
2000-09-01
Budget End
2001-08-31
Support Year
2
Fiscal Year
2000
Total Cost
$272,155
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Genetics
Type
Schools of Medicine
DUNS #
791277940
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Krebs, Christopher J; Zhang, Deqiang; Yin, Lei et al. (2014) The KRAB zinc finger protein RSL1 modulates sex-biased gene expression in liver and adipose tissue to maintain metabolic homeostasis. Mol Cell Biol 34:221-32
Krebs, Christopher J; Schultz, David C; Robins, Diane M (2012) The KRAB zinc finger protein RSL1 regulates sex- and tissue-specific promoter methylation and dynamic hormone-responsive chromatin configuration. Mol Cell Biol 32:3732-42
Krebs, Christopher J; Robins, Diane M (2010) A pair of mouse KRAB zinc finger proteins modulates multiple indicators of female reproduction. Biol Reprod 82:662-8
Krebs, Christopher J; Khan, Shaema; MacDonald, James W et al. (2009) Regulator of sex-limitation KRAB zinc finger proteins modulate sex-dependent and -independent liver metabolism. Physiol Genomics 38:16-28
Krebs, Christopher J; Khan, Shaema M; Mollard, Brett et al. (2006) Adapter annealing to engineer restriction enzyme sites at cloning junctions. Anal Biochem 350:313-5
Krebs, Christopher J; Larkins, Leslie K; Khan, Shaema M et al. (2005) Expansion and diversification of KRAB zinc-finger genes within a cluster including Regulator of sex-limitation 1 and 2. Genomics 85:752-61
Tullis, Kathryn M; Krebs, Christopher J; Leung, Janet Y M et al. (2003) The regulator of sex-limitation gene, rsl, enforces male-specific liver gene expression by negative regulation. Endocrinology 144:1854-60