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ZBTB20 is required for anterior pituitary development and lactotrope specification.

Cao D, Ma X, Cai J, Luan J, Liu AJ, Yang R, Cao Y, Zhu X, Zhang H, Chen YX, Shi Y, Shi GX, Zou D, Cao X, Grusby MJ, Xie Z, Zhang WJ - Nat Commun (2016)

Bottom Line: Disruption of Zbtb20 leads to anterior pituitary hypoplasia, hypopituitary dwarfism and a complete loss of mature lactotropes.Furthermore, endogenous ZBTB20 protein binds to Prl promoter, and its knockdown decreases PRL expression and secretion in a lactotrope cell line MMQ.In addition, ZBTB20 overexpression enhances the transcriptional activity of Prl promoter in vitro.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathophysiology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China.

ABSTRACT
The anterior pituitary harbours five distinct hormone-producing cell types, and their cellular differentiation is a highly regulated and coordinated process. Here we show that ZBTB20 is essential for anterior pituitary development and lactotrope specification in mice. In anterior pituitary, ZBTB20 is highly expressed by all the mature endocrine cell types, and to some less extent by somatolactotropes, the precursors of prolactin (PRL)-producing lactotropes. Disruption of Zbtb20 leads to anterior pituitary hypoplasia, hypopituitary dwarfism and a complete loss of mature lactotropes. In ZBTB20- mice, although lactotrope lineage commitment is normally initiated, somatolactotropes exhibit profound defects in lineage specification and expansion. Furthermore, endogenous ZBTB20 protein binds to Prl promoter, and its knockdown decreases PRL expression and secretion in a lactotrope cell line MMQ. In addition, ZBTB20 overexpression enhances the transcriptional activity of Prl promoter in vitro. In conclusion, our findings point to ZBTB20 as a critical regulator of anterior pituitary development and lactotrope specification.

No MeSH data available.


Related in: MedlinePlus

Analysis of Pit-1 expression in anterior pituitary.(a) Quantification of Pit1 mRNA level at the indicated stages in Zbtb20+/+ and Zbtb20−/− mice by real-time RT–PCR. Results are presented as fold induction relative to mRNA levels in wild-type mice. A sample was pooled from four adenohypophyses of the same phenotype, and the experiment was repeated two times. Values represent mean±s.e.m. **P<0.01 (Student's t-test). (b) Western blot of Pit1 proteins in pituitary extracts from 14-day-old Zbtb20+/+ and Zbtb20−/− mice. A sample was pooled from five to eight adenohypophyses of the same phenotype, and the experiment was repeated twice. (c,d) Immunohistochemical double staining of Pit1 (red) and GH or PRL (green) is performed at the indicated stages in Zbtb20+/+ and Zbtb20−/− pituitaries. Cell nuclei are stained with DAPI (blue). Arrowheads indicate PRL-positive cells. Scale bar, 25 μm.
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f6: Analysis of Pit-1 expression in anterior pituitary.(a) Quantification of Pit1 mRNA level at the indicated stages in Zbtb20+/+ and Zbtb20−/− mice by real-time RT–PCR. Results are presented as fold induction relative to mRNA levels in wild-type mice. A sample was pooled from four adenohypophyses of the same phenotype, and the experiment was repeated two times. Values represent mean±s.e.m. **P<0.01 (Student's t-test). (b) Western blot of Pit1 proteins in pituitary extracts from 14-day-old Zbtb20+/+ and Zbtb20−/− mice. A sample was pooled from five to eight adenohypophyses of the same phenotype, and the experiment was repeated twice. (c,d) Immunohistochemical double staining of Pit1 (red) and GH or PRL (green) is performed at the indicated stages in Zbtb20+/+ and Zbtb20−/− pituitaries. Cell nuclei are stained with DAPI (blue). Arrowheads indicate PRL-positive cells. Scale bar, 25 μm.

Mentions: Considering the pivotal role of Pit-1 in the lineage development of somatotropes and lactotropes, we then analysed Pit-1 expression in the mutant pituitary. RT–PCR and in situ hybridization analyses revealed that Pit-1 mRNA expression levels were comparable between control and mutant pituitary at P0 and P2 (Fig. 6a; Supplementary Fig. 8a), and immunohistochemical staining showed no significant difference of Pit-1 protein expression between the two groups at E18.5 (Supplementary Fig. 8b).These data suggest that Pit-1 expression is not altered in the perinatal pituitary by the loss of ZBTB20. However, RT–PCR and western blot analyses revealed that ZBTB20 deletion led to a marked reduction in Pit-1 expression at both mRNA and protein levels in the pituitary at P14 (Fig. 6a,b). To determine whether ZBTB20 disruption resulted in a decrease in Pit-1 expression in somatotropes per se, we further performed double immunostaining of Pit-1 and GH. There was no significant difference of Pit-1 staining intensity in somatotropes between the two genotypes at P7 or P14 (Fig. 6c), which suggests that decreased Pit-1 expression in mutant pituitary most likely reflects the loss of Pit-1-expressing lactotropes and somatotropes. On the other hand, Pit-1 and PRL double staining showed that Pit-1 expression in PRL-positive cells was comparable between control and mutant pituitary at birth (Fig. 6d), suggesting that the defect of lactotrope specification in the absence of ZBTB20 was not likely due to the reduction of Pit-1 expression per se.


ZBTB20 is required for anterior pituitary development and lactotrope specification.

Cao D, Ma X, Cai J, Luan J, Liu AJ, Yang R, Cao Y, Zhu X, Zhang H, Chen YX, Shi Y, Shi GX, Zou D, Cao X, Grusby MJ, Xie Z, Zhang WJ - Nat Commun (2016)

Analysis of Pit-1 expression in anterior pituitary.(a) Quantification of Pit1 mRNA level at the indicated stages in Zbtb20+/+ and Zbtb20−/− mice by real-time RT–PCR. Results are presented as fold induction relative to mRNA levels in wild-type mice. A sample was pooled from four adenohypophyses of the same phenotype, and the experiment was repeated two times. Values represent mean±s.e.m. **P<0.01 (Student's t-test). (b) Western blot of Pit1 proteins in pituitary extracts from 14-day-old Zbtb20+/+ and Zbtb20−/− mice. A sample was pooled from five to eight adenohypophyses of the same phenotype, and the experiment was repeated twice. (c,d) Immunohistochemical double staining of Pit1 (red) and GH or PRL (green) is performed at the indicated stages in Zbtb20+/+ and Zbtb20−/− pituitaries. Cell nuclei are stained with DAPI (blue). Arrowheads indicate PRL-positive cells. Scale bar, 25 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4835541&req=5

f6: Analysis of Pit-1 expression in anterior pituitary.(a) Quantification of Pit1 mRNA level at the indicated stages in Zbtb20+/+ and Zbtb20−/− mice by real-time RT–PCR. Results are presented as fold induction relative to mRNA levels in wild-type mice. A sample was pooled from four adenohypophyses of the same phenotype, and the experiment was repeated two times. Values represent mean±s.e.m. **P<0.01 (Student's t-test). (b) Western blot of Pit1 proteins in pituitary extracts from 14-day-old Zbtb20+/+ and Zbtb20−/− mice. A sample was pooled from five to eight adenohypophyses of the same phenotype, and the experiment was repeated twice. (c,d) Immunohistochemical double staining of Pit1 (red) and GH or PRL (green) is performed at the indicated stages in Zbtb20+/+ and Zbtb20−/− pituitaries. Cell nuclei are stained with DAPI (blue). Arrowheads indicate PRL-positive cells. Scale bar, 25 μm.
Mentions: Considering the pivotal role of Pit-1 in the lineage development of somatotropes and lactotropes, we then analysed Pit-1 expression in the mutant pituitary. RT–PCR and in situ hybridization analyses revealed that Pit-1 mRNA expression levels were comparable between control and mutant pituitary at P0 and P2 (Fig. 6a; Supplementary Fig. 8a), and immunohistochemical staining showed no significant difference of Pit-1 protein expression between the two groups at E18.5 (Supplementary Fig. 8b).These data suggest that Pit-1 expression is not altered in the perinatal pituitary by the loss of ZBTB20. However, RT–PCR and western blot analyses revealed that ZBTB20 deletion led to a marked reduction in Pit-1 expression at both mRNA and protein levels in the pituitary at P14 (Fig. 6a,b). To determine whether ZBTB20 disruption resulted in a decrease in Pit-1 expression in somatotropes per se, we further performed double immunostaining of Pit-1 and GH. There was no significant difference of Pit-1 staining intensity in somatotropes between the two genotypes at P7 or P14 (Fig. 6c), which suggests that decreased Pit-1 expression in mutant pituitary most likely reflects the loss of Pit-1-expressing lactotropes and somatotropes. On the other hand, Pit-1 and PRL double staining showed that Pit-1 expression in PRL-positive cells was comparable between control and mutant pituitary at birth (Fig. 6d), suggesting that the defect of lactotrope specification in the absence of ZBTB20 was not likely due to the reduction of Pit-1 expression per se.

Bottom Line: Disruption of Zbtb20 leads to anterior pituitary hypoplasia, hypopituitary dwarfism and a complete loss of mature lactotropes.Furthermore, endogenous ZBTB20 protein binds to Prl promoter, and its knockdown decreases PRL expression and secretion in a lactotrope cell line MMQ.In addition, ZBTB20 overexpression enhances the transcriptional activity of Prl promoter in vitro.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathophysiology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China.

ABSTRACT
The anterior pituitary harbours five distinct hormone-producing cell types, and their cellular differentiation is a highly regulated and coordinated process. Here we show that ZBTB20 is essential for anterior pituitary development and lactotrope specification in mice. In anterior pituitary, ZBTB20 is highly expressed by all the mature endocrine cell types, and to some less extent by somatolactotropes, the precursors of prolactin (PRL)-producing lactotropes. Disruption of Zbtb20 leads to anterior pituitary hypoplasia, hypopituitary dwarfism and a complete loss of mature lactotropes. In ZBTB20- mice, although lactotrope lineage commitment is normally initiated, somatolactotropes exhibit profound defects in lineage specification and expansion. Furthermore, endogenous ZBTB20 protein binds to Prl promoter, and its knockdown decreases PRL expression and secretion in a lactotrope cell line MMQ. In addition, ZBTB20 overexpression enhances the transcriptional activity of Prl promoter in vitro. In conclusion, our findings point to ZBTB20 as a critical regulator of anterior pituitary development and lactotrope specification.

No MeSH data available.


Related in: MedlinePlus