Trithorax maintains the functional heterogeneity of neural stem cells through the transcription factor Buttonhead
Abstract
The mechanisms that maintain the functional heterogeneity of stem cells, which generates diverse differentiated cell types required for organogenesis, are not understood. Here, we report that Trithorax (Trx) actively maintains the heterogeneity of neural stem cells (neuroblasts) in the developing Drosophila larval brain. trx mutant type II neuroblasts gradually adopt a type I neuroblast functional identity, losing the competence to generate intermediate neural progenitors (INPs) and directly generating differentiated cells. Trx regulates a type II neuroblast functional identity in part by maintaining chromatin in the buttonhead (btd) locus in an active state through the histone methyltransferase activity of the SET1/MLL complex. Consistently, btd is necessary and sufficient for eliciting a type II neuroblast functional identity. Furthermore, over-expression of btd restores the competence to generate INPs in trx mutant type II neuroblasts. Thus, Trx instructs a type II neuroblast functional identity by epigenetically promoting Btd expression, thereby maintaining neuroblast functional heterogeneity.
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© 2014, Komori et al.
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Further reading
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- Stem Cells and Regenerative Medicine
- Developmental Biology
In the developing fruit fly brain, a protein called Trithorax increases the number of neural cells produced from a single stem cell, in part by regulating the transcription of the target genes buttonhead and pointed.
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- Stem Cells and Regenerative Medicine
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