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Development. 2019 Sep 19;146(18). pii: dev177063. doi: 10.1242/dev.177063.

Transcriptional autoregulation of zebrafish tbx6 is required for somite segmentation.

Author information

1
Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan.
2
Exploratory Research Center on Life and Living Systems and National Institute for Basic Biology, National Institutes of Natural Sciences, Aichi 444-8787, Japan.
3
Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan akawamur@mail.saitama-u.ac.jp.

Abstract

The presumptive somite boundary in the presomitic mesoderm (PSM) is defined by the anterior border of the expression domain of Tbx6 protein. During somite segmentation, the expression domain of Tbx6 is regressed by Ripply-meditated degradation of Tbx6 protein. Although the expression of zebrafish tbx6 remains restricted to the PSM, the transcriptional regulation of tbx6 remains poorly understood. Here, we show that the expression of zebrafish tbx6 is maintained by transcriptional autoregulation. We find that a proximal-located cis-regulatory module, TR1, which contains two putative T-box sites, is required for somite segmentation in the intermediate body and for proper expression of segmentation genes. Embryos with deletion of TR1 exhibit significant reduction of tbx6 expression at the 12-somite stage, although its expression is initially observed. Additionally, Tbx6 is associated with TR1 and activates its own expression in the anterior PSM. Furthermore, the anterior expansion of tbx6 expression in ripply gene mutants is suppressed in a TR1-dependent manner. The results suggest that the autoregulatory loop of zebrafish tbx6 facilitates immediate removal of Tbx6 protein through termination of its own transcription at the anterior PSM.

KEYWORDS:

Enhancer; Somite segmentation; T-box transcription factor; Transcriptional regulation; Zebrafish

PMID:
31444219
DOI:
10.1242/dev.177063

Conflict of interest statement

Competing interestsThe authors declare no competing or financial interests.

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