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Sexually Dimorphic Expression of eGFP Transgene in the Akr1A1 Locus of Mouse Liver Regulated by Sex Hormone-Related Epigenetic Remodeling.

Lai CW, Chen HL, Tsai TC, Chu TW, Yang SH, Chong KY, Chen CM - Sci Rep (2016)

Bottom Line: However, the mechanism of sexually dimorphic expression is still not fully understood.In this study, a pCAG-eGFP transgenic mouse strain with a specific transgene integration site in the Akr1A1 locus presented male-biased EGFP expression in the liver, and the expression was activated by testosterone during puberty.The integration of the pCAG-eGFP transgene altered the epigenetic regulation of the adjacent chromatin, including increased binding of STAT5b, a sexually dimorphic expression regulator, and the transformation of DNA methylation from hypermethylation into male-biased hypomethylation.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences, and Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan.

ABSTRACT
Sexually dimorphic gene expression is commonly found in the liver, and many of these genes are linked to different incidences of liver diseases between sexes. However, the mechanism of sexually dimorphic expression is still not fully understood. In this study, a pCAG-eGFP transgenic mouse strain with a specific transgene integration site in the Akr1A1 locus presented male-biased EGFP expression in the liver, and the expression was activated by testosterone during puberty. The integration of the pCAG-eGFP transgene altered the epigenetic regulation of the adjacent chromatin, including increased binding of STAT5b, a sexually dimorphic expression regulator, and the transformation of DNA methylation from hypermethylation into male-biased hypomethylation. Through this de novo sexually dimorphic expression of the transgene, the Akr1A1(eGFP) mouse provides a useful model to study the mechanisms and the dynamic changes of sexually dimorphic gene expression during either development or pathogenesis of the liver.

No MeSH data available.


Related in: MedlinePlus

The male-biased EGFP expression in the liver of the pCAG-eGFP Tg mouse line.(A) The in vivo EGFP fluorescence (Akr1A1eGFP/+) (a, b) and IHC of EGFP expression (Akr1A1eGFP/eGFP and Akr1A1eGFP/+) (c–f) in livers of the male and female Tg mice, and the schematic diagram of EGFP expression in the hepatic lobule (g, h). Scale bar: 400 μm; CV: central vein; PT: portal triad. (B) The cell counts of the EGFP+ and EGFP− hepatocytes, which were isolated from male and female Akr1A1eGFP/+ mice, were analyzed by flow cytometry. Similar results were shown in five animals of each group (n = 5).
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f3: The male-biased EGFP expression in the liver of the pCAG-eGFP Tg mouse line.(A) The in vivo EGFP fluorescence (Akr1A1eGFP/+) (a, b) and IHC of EGFP expression (Akr1A1eGFP/eGFP and Akr1A1eGFP/+) (c–f) in livers of the male and female Tg mice, and the schematic diagram of EGFP expression in the hepatic lobule (g, h). Scale bar: 400 μm; CV: central vein; PT: portal triad. (B) The cell counts of the EGFP+ and EGFP− hepatocytes, which were isolated from male and female Akr1A1eGFP/+ mice, were analyzed by flow cytometry. Similar results were shown in five animals of each group (n = 5).

Mentions: Using in vivo fluorescence imaging, livers from male and female mice were easily discriminated; the livers from females displayed green fluorescent spots, and the livers from males displayed a uniform distribution of green fluorescence (Fig. 3A(a,b)). The histological analysis of the EGFP expression in liver sections revealed that EGFP expression in the livers from females was restricted in the hepatocytes around the central vein of the hepatic lobule. In the livers from males, the hepatocytes with EGFP expression also surrounded the central vein, but the expression area was extended to the boundary of the hepatic lobule (Fig. 3A(c–h) and Supplementary Fig. S1). To accurately calculate the proportion of EGFP positive (EGFP+) and EGFP negative (EGFP−) hepatocytes in the livers, the hepatocytes were isolated and analyzed by flow cytometry. The results showed that less than 5% of EGFP+ and over 95% of EGFP+ hepatocytes were found in the livers of female and male mice, respectively (Fig. 3B). Similar results were found by quantitative RT-PCR (Q-PCR) analysis of the EGFP expression (Fig. 2E), which demonstrated male-biased EGFP expression in the Tg mouse liver.


Sexually Dimorphic Expression of eGFP Transgene in the Akr1A1 Locus of Mouse Liver Regulated by Sex Hormone-Related Epigenetic Remodeling.

Lai CW, Chen HL, Tsai TC, Chu TW, Yang SH, Chong KY, Chen CM - Sci Rep (2016)

The male-biased EGFP expression in the liver of the pCAG-eGFP Tg mouse line.(A) The in vivo EGFP fluorescence (Akr1A1eGFP/+) (a, b) and IHC of EGFP expression (Akr1A1eGFP/eGFP and Akr1A1eGFP/+) (c–f) in livers of the male and female Tg mice, and the schematic diagram of EGFP expression in the hepatic lobule (g, h). Scale bar: 400 μm; CV: central vein; PT: portal triad. (B) The cell counts of the EGFP+ and EGFP− hepatocytes, which were isolated from male and female Akr1A1eGFP/+ mice, were analyzed by flow cytometry. Similar results were shown in five animals of each group (n = 5).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834580&req=5

f3: The male-biased EGFP expression in the liver of the pCAG-eGFP Tg mouse line.(A) The in vivo EGFP fluorescence (Akr1A1eGFP/+) (a, b) and IHC of EGFP expression (Akr1A1eGFP/eGFP and Akr1A1eGFP/+) (c–f) in livers of the male and female Tg mice, and the schematic diagram of EGFP expression in the hepatic lobule (g, h). Scale bar: 400 μm; CV: central vein; PT: portal triad. (B) The cell counts of the EGFP+ and EGFP− hepatocytes, which were isolated from male and female Akr1A1eGFP/+ mice, were analyzed by flow cytometry. Similar results were shown in five animals of each group (n = 5).
Mentions: Using in vivo fluorescence imaging, livers from male and female mice were easily discriminated; the livers from females displayed green fluorescent spots, and the livers from males displayed a uniform distribution of green fluorescence (Fig. 3A(a,b)). The histological analysis of the EGFP expression in liver sections revealed that EGFP expression in the livers from females was restricted in the hepatocytes around the central vein of the hepatic lobule. In the livers from males, the hepatocytes with EGFP expression also surrounded the central vein, but the expression area was extended to the boundary of the hepatic lobule (Fig. 3A(c–h) and Supplementary Fig. S1). To accurately calculate the proportion of EGFP positive (EGFP+) and EGFP negative (EGFP−) hepatocytes in the livers, the hepatocytes were isolated and analyzed by flow cytometry. The results showed that less than 5% of EGFP+ and over 95% of EGFP+ hepatocytes were found in the livers of female and male mice, respectively (Fig. 3B). Similar results were found by quantitative RT-PCR (Q-PCR) analysis of the EGFP expression (Fig. 2E), which demonstrated male-biased EGFP expression in the Tg mouse liver.

Bottom Line: However, the mechanism of sexually dimorphic expression is still not fully understood.In this study, a pCAG-eGFP transgenic mouse strain with a specific transgene integration site in the Akr1A1 locus presented male-biased EGFP expression in the liver, and the expression was activated by testosterone during puberty.The integration of the pCAG-eGFP transgene altered the epigenetic regulation of the adjacent chromatin, including increased binding of STAT5b, a sexually dimorphic expression regulator, and the transformation of DNA methylation from hypermethylation into male-biased hypomethylation.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences, and Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan.

ABSTRACT
Sexually dimorphic gene expression is commonly found in the liver, and many of these genes are linked to different incidences of liver diseases between sexes. However, the mechanism of sexually dimorphic expression is still not fully understood. In this study, a pCAG-eGFP transgenic mouse strain with a specific transgene integration site in the Akr1A1 locus presented male-biased EGFP expression in the liver, and the expression was activated by testosterone during puberty. The integration of the pCAG-eGFP transgene altered the epigenetic regulation of the adjacent chromatin, including increased binding of STAT5b, a sexually dimorphic expression regulator, and the transformation of DNA methylation from hypermethylation into male-biased hypomethylation. Through this de novo sexually dimorphic expression of the transgene, the Akr1A1(eGFP) mouse provides a useful model to study the mechanisms and the dynamic changes of sexually dimorphic gene expression during either development or pathogenesis of the liver.

No MeSH data available.


Related in: MedlinePlus