scholarly journals Delilah, prospero, and D-Pax2 constitute a gene regulatory network essential for the development of functional proprioceptors

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Adel Avetisyan ◽  
Yael Glatt ◽  
Maya Cohen ◽  
Yael Timerman ◽  
Nitay Aspis ◽  
...  

Coordinated animal locomotion depends on the development of functional proprioceptors. While early cell-fate determination processes are well characterized, little is known about the terminal differentiation of cells within the proprioceptive lineage and the genetic networks that control them. In this work we describe a gene regulatory network consisting of three transcription factors–Prospero (Pros), D-Pax2, and Delilah (Dei)–that dictates two alternative differentiation programs within the proprioceptive lineage in Drosophila. We show that D-Pax2 and Pros control the differentiation of cap versus scolopale cells in the chordotonal organ lineage by, respectively, activating and repressing the transcription of dei. Normally, D-Pax2 activates the expression of dei in the cap cell but is unable to do so in the scolopale cell where Pros is co-expressed. We further show that D-Pax2 and Pros exert their effects on dei transcription via a 262 bp chordotonal-specific enhancer in which two D-Pax2- and three Pros-binding sites were identified experimentally. When this enhancer was removed from the fly genome, the cap- and ligament-specific expression of dei was lost, resulting in loss of chordotonal organ functionality and defective larval locomotion. Thus, coordinated larval locomotion depends on the activity of a dei enhancer that integrates both activating and repressive inputs for the generation of a functional proprioceptive organ.

2021 ◽  
Author(s):  
Adel Avetisyan ◽  
Yael Glatt ◽  
Maya Cohen ◽  
Yael Timerman ◽  
Nitay Aspis ◽  
...  

In this work we describe a gene regulatory network consisting of three transcription factors- Prospero (Pros), D-Pax2/Shaven (Sv) and Delilah/Taxi (Dei/Tx)- that dictates two alternative differentiation programs within the proprioceptive lineage in Drosophila. D-Pax2 and Pros control the differentiation of cap versus scolopale cells in the chordotonal organ lineage by, respectively, activating and repressing the transcription of dei. Normally, D-Pax2 activates the expression of dei in the cap cell but is unable to do so in the scolopale cell where Pros is co-expressed. If D-Pax2 activity is lost, the cap cell fails to express dei as well as additional proteins, such as αTub85E, that characterize a fully differentiated cap cell. In contrast, if Pros activity is lost, dei is ectopically expressed in the scolopale cell that, as a consequence, adopts some cap cell features, including the expression of αTub85E. We further show that D-Pax2 and Pros exert their effects on dei transcription via a 262 bp chordotonal-specific regulatory module (deiChO-262) in which two D-Pax2- and three Pros-binding sites were identified experimentally. When this regulatory element was removed from the fly genome, the cap- and ligament-specific expression of dei was lost. Ectopic expression of D-Pax2, or the elimination of pros activity, did not lead to upregulation of dei in the scolopale cell in the absence of the D-Pax2-responsive deiChO-262 enhancer. Finally, we show that the regulation of dei expression via the D-Pax2/Pros-responsive element is critical for chordotonal organ functionality and coordinated larval locomotion.


2021 ◽  
Author(s):  
Matthias Christian Vogg ◽  
Jaroslav Ferenc ◽  
Wanda Christa Buzgariu ◽  
Chrystelle Perruchoud ◽  
Panagiotis Papasaikas ◽  
...  

The molecular mechanisms that maintain cell identities and prevent transdifferentiation remain mysterious. Interestingly, both dedifferentiation and transdifferentiation are transiently reshuffled during regeneration. Therefore, organisms that regenerate readily offer a fruitful paradigm to investigate the regulation of cell fate stability. Here, we used Hydra as a model system and show that Zic4 silencing is sufficient to induce transdifferentiation of tentacle into foot cells. We identified a Wnt-controlled Gene Regulatory Network that controls a transcriptional switch of cell identity. Furthermore, we show that this switch also controls the re-entry into the cell cycle. Our data indicate that maintenance of cell fate by a Wnt-controlled GRN is a key mechanism during both homeostasis and regeneration.


2019 ◽  
Author(s):  
Taylor N. Medwig-Kinney ◽  
Jayson J. Smith ◽  
Nicholas J. Palmisano ◽  
Sujata Tank ◽  
Wan Zhang ◽  
...  

ABSTRACTCellular invasion is a key part of development, immunity, and disease. Using thein vivomodel ofC. elegansanchor cell invasion, we characterize the gene regulatory network that promotes invasive differentiation. The anchor cell is initially specified in a stochastic cell fate decision mediated by Notch signaling. Previous research has identified four conserved transcription factors,fos-1a(Fos),egl-43(EVI1/MEL),hlh-2(E/Daughterless) andnhr-67(NR2E1/TLX), that mediate anchor cell specification and/or invasive differentiation. Connections between these transcription factors and the underlying cell biology that they regulate is poorly understood. Here, using genome editing and RNA interference, we examine transcription factor interactions prior to and after anchor cell specification. During invasion we identify thategl-43,hlh-2, andnhr-67function together in a type I coherent feed-forward loop with positive feedback. Conversely, prior to specification, these transcription factors function independent of one another to regulate LIN-12 (Notch) activity. Together, these results demonstrate that, although the same transcription factors can function in fate specification and differentiated cell behavior, a gene regulatory network can be rapidly re-wired to reinforce a post-mitotic, pro-invasive state.SUMMARY STATEMENTBasement membrane invasion by theC. elegansanchor cell is coordinated by a dynamic gene regulatory network encompassing cell cycle dependent and independent sub-circuits.


Author(s):  
Hidenori Nishihara

Abstract Acquisition of cis-elements is a major driving force for rewiring a gene regulatory network. Several kinds of transposable elements (TEs), mostly retrotransposons that propagate via a copy-and-paste mechanism, are known to possess transcription factor binding motifs and have provided source sequences for enhancers/promoters. However, it remains largely unknown whether retrotransposons have spread the binding sites of master regulators of morphogenesis and accelerated cis-regulatory expansion involved in common mammalian morphological features during evolution. Here, I demonstrate that thousands of binding sites for estrogen receptor α (ERα) and three related pioneer factors (FoxA1, GATA3 and AP2γ) that are essential regulators of mammary gland development arose from a spreading of the binding motifs by retrotransposons. The TE-derived functional elements serve primarily as distal enhancers and are enriched around genes associated with mammary gland morphogenesis. The source TEs occurred via a two-phased expansion consisting of mainly L2/MIR in a eutherian ancestor and endogenous retrovirus 1 (ERV1) in simian primates and murines. Thus the build-up of potential sources for cis-elements by retrotransposons followed by their frequent utilization by the host (co-option/exaptation) may have a general accelerating effect on both establishing and diversifying a gene regulatory network, leading to morphological innovation.


2017 ◽  
Vol 114 (23) ◽  
pp. 5800-5807 ◽  
Author(s):  
William J. R. Longabaugh ◽  
Weihua Zeng ◽  
Jingli A. Zhang ◽  
Hiroyuki Hosokawa ◽  
Camden S. Jansen ◽  
...  

T-cell development from hematopoietic progenitors depends on multiple transcription factors, mobilized and modulated by intrathymic Notch signaling. Key aspects of T-cell specification network architecture have been illuminated through recent reports defining roles of transcription factors PU.1, GATA-3, and E2A, their interactions with Notch signaling, and roles of Runx1, TCF-1, and Hes1, providing bases for a comprehensively updated model of the T-cell specification gene regulatory network presented herein. However, the role of lineage commitment factor Bcl11b has been unclear. We use self-organizing maps on 63 RNA-seq datasets from normal and perturbed T-cell development to identify functional targets of Bcl11b during commitment and relate them to other regulomes. We show that both activation and repression target genes can be bound by Bcl11b in vivo, and that Bcl11b effects overlap with E2A-dependent effects. The newly clarified role of Bcl11b distinguishes discrete components of commitment, resolving how innate lymphoid, myeloid, and dendritic, and B-cell fate alternatives are excluded by different mechanisms.


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