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Expression of Groucho/TLE proteins during pancreas development.

Hoffman BG, Zavaglia B, Beach M, Helgason CD - BMC Dev. Biol. (2008)

Bottom Line: Of note, Tle2 and Tle3 are co-expressed with Gro/TLE interaction domain containing transcription factors that are essential for endocrine pancreas development.We further demonstrate that Tle2 can interact with several of these factors and that Tle2 modulate Arx's repressive activity.Taken together our studies suggest that Gro/TLE proteins play a role in the repression of target genes during endocrine cell specification.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Cancer Endocrinology, BC Cancer Research Center, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3, Canada. bhoffman@bccrc.ca

ABSTRACT

Background: The full-length mammalian homologs of groucho, Tle1, 2, 3, and 4, act as transcriptional corepressors and are recruited by transcription factors containing an eh1 or WRPW/Y domain. Many transcription factors critical to pancreas development contain a Gro/TLE interaction domain and several have been shown to require Gro/TLE interactions for proper function during neuronal development. However, a detailed analysis of the expression patterns of the Gro/TLE proteins in pancreas development has not been performed. Moreover, little is known about the ability of Gro/TLE proteins to interact with transcription factors in the pancreas.

Results: We describe the expression of Gro/TLE family members, and of 34 different transcription factors that contain a Gro/TLE interaction motif, in the pancreas utilizing nine SAGE libraries created from the developing and adult pancreas, as well as the GenePaint database. Next, we show the dynamic expression of Tle1, 2, 3, 4, 5 and 6 during pancreas development by qRT-PCR. To further define the cell-type specificity of the expression of these proteins we use immunofluorescence to co-localize them with Pdx1 at embryonic day 12.5 (E12.5), Ngn3 at E14.5, Pdx1, Nkx2-2, Insulin, Glucagon, Pancreatic polypeptide and Somatostatin at E18.5, as well as Insulin and Glucagon in the adult. We then show that Tle2 can interact with Nkx2-2, Hes1, Arx, and Nkx6-1 which are all critical factors in pancreas development. Finally, we demonstrate that Tle2 modulates the repressive abilities of Arx in a beta-cell line.

Conclusion: Although Tle1, 2, 3, and 4 show overlapping expression in pancreatic progenitors and in the adult islet, the expression of these factors is restricted to different cell types during endocrine cell maturation. Of note, Tle2 and Tle3 are co-expressed with Gro/TLE interaction domain containing transcription factors that are essential for endocrine pancreas development. We further demonstrate that Tle2 can interact with several of these factors and that Tle2 modulate Arx's repressive activity. Taken together our studies suggest that Gro/TLE proteins play a role in the repression of target genes during endocrine cell specification.

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Expression of Gro/TLE family members and transcription factors with a Gro/TLE interaction domain in the developing pancreas. Images of in situ hybridization staining patterns for (A) Gro/TLE family members and (B) transcription factors with a Gro/TLE interaction domain on E14.5 whole embryo sagittal sections were obtained from the GenePaint website and magnified to show the pancreas (outlined in red).
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Figure 1: Expression of Gro/TLE family members and transcription factors with a Gro/TLE interaction domain in the developing pancreas. Images of in situ hybridization staining patterns for (A) Gro/TLE family members and (B) transcription factors with a Gro/TLE interaction domain on E14.5 whole embryo sagittal sections were obtained from the GenePaint website and magnified to show the pancreas (outlined in red).

Mentions: We then used the GenePaint database to assess the staining patterns of these genes in the E14.5 pancreas. Tle 2 and 3 both showed modest staining throughout the epithelium and mesenchyme, while Tle1 staining was found predominantly in the mesenchyme (Figure 1A and Table 2). Expression of Tle4 could not be detected at this time point in the pancreas. Tle5 and 6 on the other hand showed strong staining throughout the pancreas epithelium. Informative stain was obtained for 22 of the 34 transcription factors containing an eh1 or WRPW/Y domain detected in our SAGE libraries and 11 of these showed stain in the pancreas (Figure 1B and Table 2). The remaining 11 factors for which informative staining was produced but no stain was seen in the pancreas typically showed counts only in the Pdx1 GFP+ libraries or the E12.5 Ngn3 GFP-, including Foxa1, Foxc1, Pax1, Pax3, and Tbx2, or in libraries representing later developmental stages, including Foxd3, Nkx2-5, Tbx20, and Tlx1. Data from the literature also provided evidence of the expression of an additional four of these factors, including Hes1 [33], HlxB9 [34], Nkx6-1 [35], and Nkx6-2 [36], which are not in the GenePaint database. Thus, in addition to our SAGE data, there is independent evidence demonstrating the expression of thirteen different eh1 or WRPW/Y transcription factors (Arx, Foxa2, Foxa3, Hes1, Hes6, Hhex, HlxB9, Nkx2-2, Nkx6-1, Nkx6-2, Pou3f4, Tcf1, and Tcf2), many of which have well established roles in endocrine pancreas development.


Expression of Groucho/TLE proteins during pancreas development.

Hoffman BG, Zavaglia B, Beach M, Helgason CD - BMC Dev. Biol. (2008)

Expression of Gro/TLE family members and transcription factors with a Gro/TLE interaction domain in the developing pancreas. Images of in situ hybridization staining patterns for (A) Gro/TLE family members and (B) transcription factors with a Gro/TLE interaction domain on E14.5 whole embryo sagittal sections were obtained from the GenePaint website and magnified to show the pancreas (outlined in red).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2551604&req=5

Figure 1: Expression of Gro/TLE family members and transcription factors with a Gro/TLE interaction domain in the developing pancreas. Images of in situ hybridization staining patterns for (A) Gro/TLE family members and (B) transcription factors with a Gro/TLE interaction domain on E14.5 whole embryo sagittal sections were obtained from the GenePaint website and magnified to show the pancreas (outlined in red).
Mentions: We then used the GenePaint database to assess the staining patterns of these genes in the E14.5 pancreas. Tle 2 and 3 both showed modest staining throughout the epithelium and mesenchyme, while Tle1 staining was found predominantly in the mesenchyme (Figure 1A and Table 2). Expression of Tle4 could not be detected at this time point in the pancreas. Tle5 and 6 on the other hand showed strong staining throughout the pancreas epithelium. Informative stain was obtained for 22 of the 34 transcription factors containing an eh1 or WRPW/Y domain detected in our SAGE libraries and 11 of these showed stain in the pancreas (Figure 1B and Table 2). The remaining 11 factors for which informative staining was produced but no stain was seen in the pancreas typically showed counts only in the Pdx1 GFP+ libraries or the E12.5 Ngn3 GFP-, including Foxa1, Foxc1, Pax1, Pax3, and Tbx2, or in libraries representing later developmental stages, including Foxd3, Nkx2-5, Tbx20, and Tlx1. Data from the literature also provided evidence of the expression of an additional four of these factors, including Hes1 [33], HlxB9 [34], Nkx6-1 [35], and Nkx6-2 [36], which are not in the GenePaint database. Thus, in addition to our SAGE data, there is independent evidence demonstrating the expression of thirteen different eh1 or WRPW/Y transcription factors (Arx, Foxa2, Foxa3, Hes1, Hes6, Hhex, HlxB9, Nkx2-2, Nkx6-1, Nkx6-2, Pou3f4, Tcf1, and Tcf2), many of which have well established roles in endocrine pancreas development.

Bottom Line: Of note, Tle2 and Tle3 are co-expressed with Gro/TLE interaction domain containing transcription factors that are essential for endocrine pancreas development.We further demonstrate that Tle2 can interact with several of these factors and that Tle2 modulate Arx's repressive activity.Taken together our studies suggest that Gro/TLE proteins play a role in the repression of target genes during endocrine cell specification.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Cancer Endocrinology, BC Cancer Research Center, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3, Canada. bhoffman@bccrc.ca

ABSTRACT

Background: The full-length mammalian homologs of groucho, Tle1, 2, 3, and 4, act as transcriptional corepressors and are recruited by transcription factors containing an eh1 or WRPW/Y domain. Many transcription factors critical to pancreas development contain a Gro/TLE interaction domain and several have been shown to require Gro/TLE interactions for proper function during neuronal development. However, a detailed analysis of the expression patterns of the Gro/TLE proteins in pancreas development has not been performed. Moreover, little is known about the ability of Gro/TLE proteins to interact with transcription factors in the pancreas.

Results: We describe the expression of Gro/TLE family members, and of 34 different transcription factors that contain a Gro/TLE interaction motif, in the pancreas utilizing nine SAGE libraries created from the developing and adult pancreas, as well as the GenePaint database. Next, we show the dynamic expression of Tle1, 2, 3, 4, 5 and 6 during pancreas development by qRT-PCR. To further define the cell-type specificity of the expression of these proteins we use immunofluorescence to co-localize them with Pdx1 at embryonic day 12.5 (E12.5), Ngn3 at E14.5, Pdx1, Nkx2-2, Insulin, Glucagon, Pancreatic polypeptide and Somatostatin at E18.5, as well as Insulin and Glucagon in the adult. We then show that Tle2 can interact with Nkx2-2, Hes1, Arx, and Nkx6-1 which are all critical factors in pancreas development. Finally, we demonstrate that Tle2 modulates the repressive abilities of Arx in a beta-cell line.

Conclusion: Although Tle1, 2, 3, and 4 show overlapping expression in pancreatic progenitors and in the adult islet, the expression of these factors is restricted to different cell types during endocrine cell maturation. Of note, Tle2 and Tle3 are co-expressed with Gro/TLE interaction domain containing transcription factors that are essential for endocrine pancreas development. We further demonstrate that Tle2 can interact with several of these factors and that Tle2 modulate Arx's repressive activity. Taken together our studies suggest that Gro/TLE proteins play a role in the repression of target genes during endocrine cell specification.

Show MeSH