Dual roles of Hh signaling in the regulation of somatic stem cell self-renewal and germline stem cell maintenance in Drosophila testis
Dual roles of Hh signaling in the regulation of somatic stem cell self-renewal and germline stem cell maintenance in Drosophila testis
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DOI：
10.1038/cr.2013.29
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发表时间：
2013-02
期刊：
影响因子：
44.1
通讯作者：
Zhao Zhang;Xiangdong Lv;Jin Jiang;Lei Zhang;Yun Zhao
中科院分区：
文献类型：
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作者：
Zhao Zhang;Xiangdong Lv;Jin Jiang;Lei Zhang;Yun Zhao
Stem cell niche is a specialized microenvironment crucial for stem cell self-renewal. Drosophila testis contains two types of stem cells: germline stem cells (GSCs) and somatic cyst stem cells (CySCs), providing a good model for studying niche-stem cell interaction [1]. At the apex of testis tube, non-mitotic somatic cells form a tightly folded structure called the hub. About 10 GSCs, each accompanied by 2 CySCs, make direct contact with the hub cells to form a rose-like structure (Supplementary information, Figure S1A). CySCs rely on the hub cells for niche signals, while GSCs are maintained by niche signals from both the hub cells and CySCs [1]. Bone morphogenetic protein (BMP) signaling is critical for GSC maintenance [2], while Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling functions in both CySCs and GSCs. STAT activation in CySCs leads to the expression of zfh-1 [3] and chinmo [4], two factors critical for CySC self-renewal. JAK-STAT signaling does not directly regulate the selfrenewal of GSCs, but governs GSC-niche adhesion [5]. Although Zfh-1 is a direct target of activated STAT, eliminating STAT activity only decreased but did not abolish Zfh-1 expression [3], suggesting that a paralleled pathway (s) may be involved in the regulation of Zfh-1 expression. In the course of immunostaining adult flies expressing a hh enhancer trap, hh-lacZ [6], we observed a strong hh-lacZ staining at the apex of testis (Supplementary information, Figure S1), which is consistent with a previous observation that hh-lacZ was expressed in the hub cells [6], suggesting a potential function of Hedgehog (Hh) signaling in the testis. We examined the expression of several core components of the Hh pathway. Hh is expressed in the hub cells as revealed by hh-lacZ and Hh stainings (Supplementary information, Figure S1), which is consistent with a recent finding from Michel M et al.[7]. The stainings of Ci-lacZ, Ci, ptc-lacZ and Smo largely coincide with that of Zfh-1 expression (Supplementary information,
