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Identification of candidate genes for human pituitary development by EST analysis.

Ma Y, Qi X, Du J, Song S, Feng D, Qi J, Zhu Z, Zhang X, Xiao H, Han Z, Hao X - BMC Genomics (2009)

Bottom Line: Furthermore, by using RT-PCR and in situ hybridization, Sox4 was found to be one of the main transcription factors expressed in fetal pituitary for the first time.It was expressed at least at E12.5, but decreased after E17.5.The significant changes in gene expression in both tissues suggest a distinct and dynamic switch between embryonic and adult pituitaries.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Clinical Laboratory Medicine of PLA, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, PR China. cmbmayy@fmmu.edu.cn

ABSTRACT

Background: The pituitary is a critical neuroendocrine gland that is comprised of five hormone-secreting cell types, which develops in tandem during the embryonic stage. Some essential genes have been identified in the early stage of adenohypophysial development, such as PITX1, FGF8, BMP4 and SF-1. However, it is likely that a large number of signaling molecules and transcription factors essential for determination and terminal differentiation of specific cell types remain unidentified. High-throughput methods such as microarray analysis may facilitate the measurement of gene transcriptional levels, while Expressed sequence tag (EST) sequencing, an efficient method for gene discovery and expression level analysis, may no-redundantly help to understand gene expression patterns during development.

Results: A total of 9,271 ESTs were generated from both fetal and adult pituitaries, and assigned into 961 gene/EST clusters in fetal and 2,747 in adult pituitary by homology analysis. The transcription maps derived from these data indicated that developmentally relevant genes, such as Sox4, ST13 and ZNF185, were dominant in the cDNA library of fetal pituitary, while hormones and hormone-associated genes, such as GH1, GH2, POMC, LHbeta, CHGA and CHGB, were dominant in adult pituitary. Furthermore, by using RT-PCR and in situ hybridization, Sox4 was found to be one of the main transcription factors expressed in fetal pituitary for the first time. It was expressed at least at E12.5, but decreased after E17.5. In addition, 40 novel ESTs were identified specifically in this tissue.

Conclusion: The significant changes in gene expression in both tissues suggest a distinct and dynamic switch between embryonic and adult pituitaries. All these data along with Sox4 should be confirmed to further understand the community of multiple signaling pathways that act as a cooperative network that regulates maturation of the pituitary. It was also suggested that EST sequencing is an efficient means of gene discovery.

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In situ hybridization of Sox4 in mice fetal pituitaries. A-D show the images hybridized with Sox4 probe. The positive blue color was initiated by alkaline phosphatase and BCIP/NBT. All the slides were counterstained with 0.1% nuclear fast red after in situ hybridization. Original magnification, ×200 (bar, 50 μm).
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Figure 3: In situ hybridization of Sox4 in mice fetal pituitaries. A-D show the images hybridized with Sox4 probe. The positive blue color was initiated by alkaline phosphatase and BCIP/NBT. All the slides were counterstained with 0.1% nuclear fast red after in situ hybridization. Original magnification, ×200 (bar, 50 μm).

Mentions: There were eight (0.24%) transcripts for Sox4 in the fetal pituitary ESTs, but none was found in the adult pituitary cDNA library. The expression pattern of Sox4 during pituitary development was confirmed by semi-quantitative RT-PCR of human samples. The transcript level of Sox4 was much higher in fetal pituitary but was reduced to a very low level in adult pituitary (Fig. 2). At the same time, the transcription levels of GH, PRL, POMC, TSH, FSH, LH, CGA and CART (cocaine and amphetamine regulated transcript) were increased in adult samples. To further address the issue, we examined expression of Sox4 in E12.5, E14.5 and E17.5 mouse embryos and in adult pituitary using in situ hybridization. On E12.5, Sox4 was expressed in the pituitary at modest levels in the infundibulum and RP (Fig. 3A). By E14.5, Sox4 expression was most abundant in the undifferentiated cells of the anterior, intermediate and posterior lobes (Fig. 3B), but significantly decreased at E17.5 (Fig. 3C). In adults, the pituitary is fully differentiated and contains all of the hormone-secreting cell lineages. At this time-point, Sox4 was not detected in either the anterior, intermediate or posterior lobes (Fig. 3D). The expression pattern was similar to that of the gene in pancreas [16] and tibia [17] development, which indicates that the activity of this gene is restricted to the cell specification and terminal differentiation phase of pituitary development.


Identification of candidate genes for human pituitary development by EST analysis.

Ma Y, Qi X, Du J, Song S, Feng D, Qi J, Zhu Z, Zhang X, Xiao H, Han Z, Hao X - BMC Genomics (2009)

In situ hybridization of Sox4 in mice fetal pituitaries. A-D show the images hybridized with Sox4 probe. The positive blue color was initiated by alkaline phosphatase and BCIP/NBT. All the slides were counterstained with 0.1% nuclear fast red after in situ hybridization. Original magnification, ×200 (bar, 50 μm).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2664823&req=5

Figure 3: In situ hybridization of Sox4 in mice fetal pituitaries. A-D show the images hybridized with Sox4 probe. The positive blue color was initiated by alkaline phosphatase and BCIP/NBT. All the slides were counterstained with 0.1% nuclear fast red after in situ hybridization. Original magnification, ×200 (bar, 50 μm).
Mentions: There were eight (0.24%) transcripts for Sox4 in the fetal pituitary ESTs, but none was found in the adult pituitary cDNA library. The expression pattern of Sox4 during pituitary development was confirmed by semi-quantitative RT-PCR of human samples. The transcript level of Sox4 was much higher in fetal pituitary but was reduced to a very low level in adult pituitary (Fig. 2). At the same time, the transcription levels of GH, PRL, POMC, TSH, FSH, LH, CGA and CART (cocaine and amphetamine regulated transcript) were increased in adult samples. To further address the issue, we examined expression of Sox4 in E12.5, E14.5 and E17.5 mouse embryos and in adult pituitary using in situ hybridization. On E12.5, Sox4 was expressed in the pituitary at modest levels in the infundibulum and RP (Fig. 3A). By E14.5, Sox4 expression was most abundant in the undifferentiated cells of the anterior, intermediate and posterior lobes (Fig. 3B), but significantly decreased at E17.5 (Fig. 3C). In adults, the pituitary is fully differentiated and contains all of the hormone-secreting cell lineages. At this time-point, Sox4 was not detected in either the anterior, intermediate or posterior lobes (Fig. 3D). The expression pattern was similar to that of the gene in pancreas [16] and tibia [17] development, which indicates that the activity of this gene is restricted to the cell specification and terminal differentiation phase of pituitary development.

Bottom Line: Furthermore, by using RT-PCR and in situ hybridization, Sox4 was found to be one of the main transcription factors expressed in fetal pituitary for the first time.It was expressed at least at E12.5, but decreased after E17.5.The significant changes in gene expression in both tissues suggest a distinct and dynamic switch between embryonic and adult pituitaries.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Clinical Laboratory Medicine of PLA, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, PR China. cmbmayy@fmmu.edu.cn

ABSTRACT

Background: The pituitary is a critical neuroendocrine gland that is comprised of five hormone-secreting cell types, which develops in tandem during the embryonic stage. Some essential genes have been identified in the early stage of adenohypophysial development, such as PITX1, FGF8, BMP4 and SF-1. However, it is likely that a large number of signaling molecules and transcription factors essential for determination and terminal differentiation of specific cell types remain unidentified. High-throughput methods such as microarray analysis may facilitate the measurement of gene transcriptional levels, while Expressed sequence tag (EST) sequencing, an efficient method for gene discovery and expression level analysis, may no-redundantly help to understand gene expression patterns during development.

Results: A total of 9,271 ESTs were generated from both fetal and adult pituitaries, and assigned into 961 gene/EST clusters in fetal and 2,747 in adult pituitary by homology analysis. The transcription maps derived from these data indicated that developmentally relevant genes, such as Sox4, ST13 and ZNF185, were dominant in the cDNA library of fetal pituitary, while hormones and hormone-associated genes, such as GH1, GH2, POMC, LHbeta, CHGA and CHGB, were dominant in adult pituitary. Furthermore, by using RT-PCR and in situ hybridization, Sox4 was found to be one of the main transcription factors expressed in fetal pituitary for the first time. It was expressed at least at E12.5, but decreased after E17.5. In addition, 40 novel ESTs were identified specifically in this tissue.

Conclusion: The significant changes in gene expression in both tissues suggest a distinct and dynamic switch between embryonic and adult pituitaries. All these data along with Sox4 should be confirmed to further understand the community of multiple signaling pathways that act as a cooperative network that regulates maturation of the pituitary. It was also suggested that EST sequencing is an efficient means of gene discovery.

Show MeSH