Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA.
Development. 2023 Jan 15;150(2). doi: 10.1242/dev.201148. Epub 2023 Jan 20.
The adult Drosophila testis contains a well-defined niche created by a cluster of hub cells, which secrete signals that maintain adjacent germline stem cells and somatic cyst stem cells (CySCs). Hub cells are normally quiescent in adult flies but can exit quiescence, delaminate from the hub and convert into CySCs after ablation of all CySCs. The opposite event, CySC conversion into hub cells, was proposed to occur under physiological conditions, but the frequency of this event is debated. Here, to probe further the question of whether or not hub cells can be regenerated, we developed methods to genetically ablate some or all hub cells. Surprisingly, when flies were allowed to recover from ablation, the missing hub cells were not replaced. Hub cells did not exit quiescence after partial ablation of hub cells, and labeled cells from outside the hub did not enter the hub during or after ablation. Despite its ability to exit quiescence in response to CySC ablation, we conclude that the hub in the adult Drosophila testis does not have a mechanism to replenish missing hub cells.
成年果蝇的睾丸包含一个由一群中央细胞形成的明确小生境，这些中央细胞分泌的信号维持着邻近的生殖干细胞和体腔干细胞（CySCs）。在成年果蝇中，中央细胞通常处于静止状态，但在所有 CySCs 被剔除后，它们可以退出静止状态，从中央细胞簇中分离出来并转化为 CySCs。相反的事件，即 CySC 转化为中央细胞，据推测在生理条件下会发生，但这种事件的频率存在争议。在这里，为了进一步探讨中央细胞是否可以再生的问题，我们开发了一些方法来遗传剔除部分或全部中央细胞。令人惊讶的是，当让果蝇从剔除中恢复时，缺失的中央细胞并没有被替代。在中央细胞部分剔除后，中央细胞没有退出静止状态，而且在剔除过程中或之后，来自中央细胞外的标记细胞也没有进入中央细胞。尽管它能够响应 CySC 剔除而退出静止状态，但我们得出结论，成年果蝇睾丸的中央细胞没有机制来补充缺失的中央细胞。
