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Plakoglobin as a regulator of desmocollin gene expression.

Tokonzaba E, Chen J, Cheng X, Den Z, Ganeshan R, Műller EJ, Koch PJ - J. Invest. Dermatol. (2013)

Bottom Line: Specifically, we found that Lef-1 acts as a switch activating Dsc2 and repressing Dsc3 in the presence of Pg.Interestingly, we also determined that NF-κB pathway components, the downstream effectors of the ectodysplasin-A (EDA)/ ectodysplasin-A receptor (EDAR)/NF-κB signaling cascade, can activate Dsc2 expression.It is tempting to speculate that this shift is required for the invasive growth of placode keratinocytes into the dermis, a crucial step in skin appendage formation.

View Article: PubMed Central - PubMed

Affiliation: Department of Dermatology, University of Colorado School of Medicine, Aurora, Colorado, USA.

ABSTRACT
Desmosomes are cell adhesion junctions required for the normal development and maintenance of mammalian tissues and organs such as the skin, skin appendages, and the heart. The goal of this study was to investigate how desmocollins (DSCs), transmembrane components of desmosomes, are regulated at the transcriptional level. We hypothesized that differential expression of the Dsc2 and Dsc3 genes is a prerequisite for normal development of skin appendages. We demonstrate that plakoglobin (Pg) in conjunction with lymphoid enhancer-binding factor 1 (Lef-1) differentially regulates the proximal promoters of these two genes. Specifically, we found that Lef-1 acts as a switch activating Dsc2 and repressing Dsc3 in the presence of Pg. Interestingly, we also determined that NF-κB pathway components, the downstream effectors of the ectodysplasin-A (EDA)/ ectodysplasin-A receptor (EDAR)/NF-κB signaling cascade, can activate Dsc2 expression. We hypothesize that Lef-1 and EDA/EDAR/NF-κB signaling contribute to a shift in Dsc isoform expression from Dsc3 to Dsc2 in placode keratinocytes. It is tempting to speculate that this shift is required for the invasive growth of placode keratinocytes into the dermis, a crucial step in skin appendage formation.

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Wnt activity and Dsc3 expression during mouse appendage development(a). Whole mount in-situ staining for beta-galactosidase (β-gal) activity of a transgenic mouse (Dsc3-LacZ BAC, E15.5) expressing β-gal under the control of the Dsc3 promoter. Note that whisker pads, hair follicles and mammary glands (not shown) are strongly stained. (b) Whole mount β-gal staining of a BAT-gal transgenic mouse (Maretto et al., 2003) at E15.5. Note the similar staining patterns of the transgenic mice shown in a. and b. (c.) Immunohistochemistry staining of a skin section from a Dsc3-LacZ BAC mouse at E15.5 with (c) β-gal antibodies and (d) Lef-1 antibodies. The LacZ transgene contains a nuclear localization signal. Note that β-gal and Lef-1 expression appears to be mutually exclusive. Arrows point to Lef-1 expressing cells in a placode and a dermal papilla of a forming hair follicle. (e-g) Immunofluorescence staining of a developing hair follicle in wild type mouse skin at E16.5 with antibodies against Lef-1 and DSC3. The area demarcated by the dotted box is shown at higher magnification in panel (h). (h) The large arrow points to DSC3 positive keratinocytes in the basal cell layer. The short arrow points to DSC3-negative and Lef-1-positive cells in a forming hair placode. Dotted lines in (e-h), basement membrane area._Bar, 50μm
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Figure 4: Wnt activity and Dsc3 expression during mouse appendage development(a). Whole mount in-situ staining for beta-galactosidase (β-gal) activity of a transgenic mouse (Dsc3-LacZ BAC, E15.5) expressing β-gal under the control of the Dsc3 promoter. Note that whisker pads, hair follicles and mammary glands (not shown) are strongly stained. (b) Whole mount β-gal staining of a BAT-gal transgenic mouse (Maretto et al., 2003) at E15.5. Note the similar staining patterns of the transgenic mice shown in a. and b. (c.) Immunohistochemistry staining of a skin section from a Dsc3-LacZ BAC mouse at E15.5 with (c) β-gal antibodies and (d) Lef-1 antibodies. The LacZ transgene contains a nuclear localization signal. Note that β-gal and Lef-1 expression appears to be mutually exclusive. Arrows point to Lef-1 expressing cells in a placode and a dermal papilla of a forming hair follicle. (e-g) Immunofluorescence staining of a developing hair follicle in wild type mouse skin at E16.5 with antibodies against Lef-1 and DSC3. The area demarcated by the dotted box is shown at higher magnification in panel (h). (h) The large arrow points to DSC3 positive keratinocytes in the basal cell layer. The short arrow points to DSC3-negative and Lef-1-positive cells in a forming hair placode. Dotted lines in (e-h), basement membrane area._Bar, 50μm

Mentions: We conducted whole-mount β-galactosidase staining experiments using Dsc3-LacZ embryos (Figure 4a). At E15.5, β-galactosidase activity was prominent in whisker pads (vibrissae follicles), in mammary gland buds and in developing hair follicles over the entire body surface (Fig. 4a, and data not shown). Strikingly, the overall DSC3-LacZ expression pattern appeared similar to the staining patterns observed in transgenic embryos of the same age that expressed a TCF/Lef-regulated promoter driving a LacZ reporter [Figure 4b; Bat-Gal, (Maretto et al., 2003)]. However, a histochemical analysis revealed that the expression patterns of Wnt pathway components (Lef-1; TCF-3/-4; data not shown) and the DSC3-LacZ transgene did not overlap at the cellular level. In fact, Wnt activity (Lef-1 expression) and Dsc3 expression were mutually exclusive (Figure 4c-d). We observed that LacZ-positive (Dsc3-expressing) cells were found in the suprabasal layer on top of the newly forming hair follicles. Lef-1, on the other hand, was observed in the leading edge of keratinocytes growing down into the dermis and throughout the basal cell layer. These findings were confirmed by staining E16.5 wild type mouse epidermis with Lef-1 and DSC3 antibodies (Figure 4e-h). Strong Lef-1 antibody staining correlated with reduced or absent staining for DSC3. Unfortunately, we were not able to assess the distributions of DSC2, since antibodies that recognize mouse DSC2 are not available. Pg antibodies stained cell-cell borders in placode keratinocytes (data not shown). Nuclear Pg staining was not observed, possibly due to epitope masking or low nuclear Pg levels.


Plakoglobin as a regulator of desmocollin gene expression.

Tokonzaba E, Chen J, Cheng X, Den Z, Ganeshan R, Műller EJ, Koch PJ - J. Invest. Dermatol. (2013)

Wnt activity and Dsc3 expression during mouse appendage development(a). Whole mount in-situ staining for beta-galactosidase (β-gal) activity of a transgenic mouse (Dsc3-LacZ BAC, E15.5) expressing β-gal under the control of the Dsc3 promoter. Note that whisker pads, hair follicles and mammary glands (not shown) are strongly stained. (b) Whole mount β-gal staining of a BAT-gal transgenic mouse (Maretto et al., 2003) at E15.5. Note the similar staining patterns of the transgenic mice shown in a. and b. (c.) Immunohistochemistry staining of a skin section from a Dsc3-LacZ BAC mouse at E15.5 with (c) β-gal antibodies and (d) Lef-1 antibodies. The LacZ transgene contains a nuclear localization signal. Note that β-gal and Lef-1 expression appears to be mutually exclusive. Arrows point to Lef-1 expressing cells in a placode and a dermal papilla of a forming hair follicle. (e-g) Immunofluorescence staining of a developing hair follicle in wild type mouse skin at E16.5 with antibodies against Lef-1 and DSC3. The area demarcated by the dotted box is shown at higher magnification in panel (h). (h) The large arrow points to DSC3 positive keratinocytes in the basal cell layer. The short arrow points to DSC3-negative and Lef-1-positive cells in a forming hair placode. Dotted lines in (e-h), basement membrane area._Bar, 50μm
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC3760975&req=5

Figure 4: Wnt activity and Dsc3 expression during mouse appendage development(a). Whole mount in-situ staining for beta-galactosidase (β-gal) activity of a transgenic mouse (Dsc3-LacZ BAC, E15.5) expressing β-gal under the control of the Dsc3 promoter. Note that whisker pads, hair follicles and mammary glands (not shown) are strongly stained. (b) Whole mount β-gal staining of a BAT-gal transgenic mouse (Maretto et al., 2003) at E15.5. Note the similar staining patterns of the transgenic mice shown in a. and b. (c.) Immunohistochemistry staining of a skin section from a Dsc3-LacZ BAC mouse at E15.5 with (c) β-gal antibodies and (d) Lef-1 antibodies. The LacZ transgene contains a nuclear localization signal. Note that β-gal and Lef-1 expression appears to be mutually exclusive. Arrows point to Lef-1 expressing cells in a placode and a dermal papilla of a forming hair follicle. (e-g) Immunofluorescence staining of a developing hair follicle in wild type mouse skin at E16.5 with antibodies against Lef-1 and DSC3. The area demarcated by the dotted box is shown at higher magnification in panel (h). (h) The large arrow points to DSC3 positive keratinocytes in the basal cell layer. The short arrow points to DSC3-negative and Lef-1-positive cells in a forming hair placode. Dotted lines in (e-h), basement membrane area._Bar, 50μm
Mentions: We conducted whole-mount β-galactosidase staining experiments using Dsc3-LacZ embryos (Figure 4a). At E15.5, β-galactosidase activity was prominent in whisker pads (vibrissae follicles), in mammary gland buds and in developing hair follicles over the entire body surface (Fig. 4a, and data not shown). Strikingly, the overall DSC3-LacZ expression pattern appeared similar to the staining patterns observed in transgenic embryos of the same age that expressed a TCF/Lef-regulated promoter driving a LacZ reporter [Figure 4b; Bat-Gal, (Maretto et al., 2003)]. However, a histochemical analysis revealed that the expression patterns of Wnt pathway components (Lef-1; TCF-3/-4; data not shown) and the DSC3-LacZ transgene did not overlap at the cellular level. In fact, Wnt activity (Lef-1 expression) and Dsc3 expression were mutually exclusive (Figure 4c-d). We observed that LacZ-positive (Dsc3-expressing) cells were found in the suprabasal layer on top of the newly forming hair follicles. Lef-1, on the other hand, was observed in the leading edge of keratinocytes growing down into the dermis and throughout the basal cell layer. These findings were confirmed by staining E16.5 wild type mouse epidermis with Lef-1 and DSC3 antibodies (Figure 4e-h). Strong Lef-1 antibody staining correlated with reduced or absent staining for DSC3. Unfortunately, we were not able to assess the distributions of DSC2, since antibodies that recognize mouse DSC2 are not available. Pg antibodies stained cell-cell borders in placode keratinocytes (data not shown). Nuclear Pg staining was not observed, possibly due to epitope masking or low nuclear Pg levels.

Bottom Line: Specifically, we found that Lef-1 acts as a switch activating Dsc2 and repressing Dsc3 in the presence of Pg.Interestingly, we also determined that NF-κB pathway components, the downstream effectors of the ectodysplasin-A (EDA)/ ectodysplasin-A receptor (EDAR)/NF-κB signaling cascade, can activate Dsc2 expression.It is tempting to speculate that this shift is required for the invasive growth of placode keratinocytes into the dermis, a crucial step in skin appendage formation.

View Article: PubMed Central - PubMed

Affiliation: Department of Dermatology, University of Colorado School of Medicine, Aurora, Colorado, USA.

ABSTRACT
Desmosomes are cell adhesion junctions required for the normal development and maintenance of mammalian tissues and organs such as the skin, skin appendages, and the heart. The goal of this study was to investigate how desmocollins (DSCs), transmembrane components of desmosomes, are regulated at the transcriptional level. We hypothesized that differential expression of the Dsc2 and Dsc3 genes is a prerequisite for normal development of skin appendages. We demonstrate that plakoglobin (Pg) in conjunction with lymphoid enhancer-binding factor 1 (Lef-1) differentially regulates the proximal promoters of these two genes. Specifically, we found that Lef-1 acts as a switch activating Dsc2 and repressing Dsc3 in the presence of Pg. Interestingly, we also determined that NF-κB pathway components, the downstream effectors of the ectodysplasin-A (EDA)/ ectodysplasin-A receptor (EDAR)/NF-κB signaling cascade, can activate Dsc2 expression. We hypothesize that Lef-1 and EDA/EDAR/NF-κB signaling contribute to a shift in Dsc isoform expression from Dsc3 to Dsc2 in placode keratinocytes. It is tempting to speculate that this shift is required for the invasive growth of placode keratinocytes into the dermis, a crucial step in skin appendage formation.

Show MeSH
Related in: MedlinePlus