AP2-type transcription factors determine stem cell identity in the moss Physcomitrella patens
AP2-type transcription factors determine stem cell identity in the moss Physcomitrella patens
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DOI：
10.1242/dev.076091
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发表时间：
2012-09-01
期刊：
影响因子：
4.6
通讯作者：
Hasebe, Mitsuyasu
中科院分区：
文献类型：
--
作者：
Aoyama, Tsuyoshi;Hiwatashi, Yuji;Hasebe, Mitsuyasu
干细胞在多细胞生物体发育过程中的特定时间和位置形成。开花植物仅在孢子体世代中形成干细胞，而非种子植物在孢子体和配子体世代中都形成干细胞。虽然在孢子体世代中干细胞形成的分子机制已被广泛研究，但只有少数转录因子参与配子体干细胞形成的调控。藓类小立碗藓的原丝体和配子体分别由原丝体顶端细胞和配子体顶端细胞形成菌丝状体和芽状体。这些顶端细胞具有干细胞特征，并形成为分化的原丝体细胞的侧支。在这里，我们表明，四个AP2型转录因子orthopathic拟南芥AINTEGUMENTA，PLETHORA和婴儿的BOOM（APB）是必不可少的配子体顶端细胞的形成从原丝体细胞。四重破坏的所有APB基因阻断配子体的形成，即使在细胞分裂素的存在下，这增强了配子体顶端细胞的形成在野生型。所有的APB基因表达在新兴的配子体顶端细胞，但不是在原丝体顶端细胞。热休克诱导的APB4转基因驱动的热休克启动子增加配子体的数量。所有的APB基因的表达诱导生长素，但不是由细胞分裂素。因此，APB基因与细胞分裂素信号传导协同作用以确定两种类型干细胞的身份。
Stem cells are formed at particular times and positions during the development of multicellular organisms. Whereas flowering plants form stem cells only in the sporophyte generation, non-seed plants form stem cells in both the sporophyte and gametophyte generations. Although the molecular mechanisms underlying stem cell formation in the sporophyte generation have been extensively studied, only a few transcription factors involved in the regulation of gametophyte stem cell formation have been reported. The moss Physcomitrella patens forms a hypha-like body (protonema) and a shoot-like body (gametophore) from a protonema apical cell and a gametophore apical cell, respectively. These apical cells have stem cell characteristics and are formed as side branches of differentiated protonema cells. Here, we show that four AP2-type transcription factors orthologous to Arabidopsis thaliana AINTEGUMENTA, PLETHORA and BABY BOOM (APB) are indispensable for the formation of gametophore apical cells from protonema cells. Quadruple disruption of all APB genes blocked gametophore formation, even in the presence of cytokinin, which enhances gametophore apical cell formation in the wild type. All APB genes were expressed in emerging gametophore apical cells, but not in protonema apical cells. Heat-shock induction of an APB4 transgene driven by a heat-shock promoter increased the number of gametophores. Expression of all APB genes was induced by auxin but not by cytokinin. Thus, the APB genes function synergistically with cytokinin signaling to determine the identity of the two types of stem cells.