Biology subjects

Yang, C.-P.

Publications and source records attributed to Yang, C.-P..

3 recordsLinked to original sources

bioRxiv2017

Regulating prospero mRNA Stability Determines When Neural Stem Cells Stop Dividing

During Drosophila and vertebrate brain development, the conserved transcription factor Prospero/Prox1 is an important regulator of the transition between proliferation and differentiation. Prospero level is low in neural stem cells and their immediate progeny, but is upregulated in larval neurons and it is unknown how this process is controlled. Here, we use single molecule fluorescent in situ hybridisation to show that larval neurons selectively transcribe a long prospero mRNA isoform containing a 15 kb 3 untranslated region, which is bound in the brain by the conserved RNA-binding protein Syncrip/hnRNPQ. Syncrip binding increases the mRNA stability of the long prospero isoform, which allows an upregulation of Prospero protein production. Our findings highlight a regulatory strategy involving alternative polyadenylation followed by differential post-transcriptional regulation.

developmental biology↗

bioRxiv2017

Imp/Syp Temporal Gradients Govern Decommissioning Of Drosophila Neural Stem Cells

Timing of Drosophila neuroblast decommissioning is controlled in a lineage-specific manner. Following a prepupal ecdysone pulse, the ecdysone receptor and mediator complex cause neuroblasts to shrink. Shrinking is followed by nuclear accumulation of Prospero and cell cycle exit. Only mushroom body (MB) neuroblasts escape early pupal termination. Here, we demonstrate that the opposing temporal gradients of Imp and Syp RNA-binding proteins that govern temporal fate also regulate neuroblast decommissioning. The Imp gradient declines slower in MB neuroblasts so they still express Imp when it is absent from others. The presence of Imp in MB neuroblasts prevents decommissioning partly through inhibiting the mediator complex. Moreover, a timely induction of Imp can protect many non-MB neuroblasts from aging. We also show that the increasing Syp gradient permits Prospero accumulation and neuroblast termination. Together our results reveal that progeny temporal fate and progenitor decommissioning are co-regulated in protracted neuronal lineages.

developmental biology↗

bioRxiv2017

Stem cell intrinsic, Seven-up-triggered temporal factor gradients diversify intermediate neural progenitors

Drosophila type II neuroblasts produce numerous neurons and glia due to transiently amplifying, intermediate neural progenitors (INP). Consecutively born INPs produce morphologically distinct progeny, presumably due to temporal patterning in type II neuroblasts. We therefore profiled type II neuroblasts transcriptome across time. Our results reveal opposing temporal gradients of Imp and Syp RNA-binding proteins (descending and ascending, respectively). Maintaining Imp expression throughout brain development expands the number of neurons/glia with early temporal fate at the expense of cells with late fate. Conversely, precocious upregulation of Syp reduces the number of cells with early fate. Further, we reveal that the transcription factor, Seven-up initiates progression of the Imp/Syp gradients. Interestingly, genetic manipulations that fix Imp or Syp levels still yield progeny with a small range of early fates. We propose that the Seven-up-initiated Imp/Syp gradients create coarse temporal windows within type II neuroblasts to pattern INPs, which subsequently undergo fine-tuned subtemporal patterning.

neuroscience↗