Cell-to-cell heterogeneity in Sox2 and Bra expression guides progenitor motility and destiny.

Although cell-to-cell heterogeneity in gene and protein expression within cell populations has been widely documented, we know little about its biological functions. By studying progenitors of the posterior region of bird embryos, we found that expression levels of transcription factors Sox2 and Bra, respectively involved in neural tube (NT) and mesoderm specification, display a high degree of cell-to-cell heterogeneity. By combining forced expression and downregulation approaches with time-lapse imaging, we demonstrate that Sox2-to-Bra ratio guides progenitor's motility and their ability to stay in or exit the progenitor zone to integrate neural or mesodermal tissues.

Transcriptome profiling of the Olig2-expressing astrocyte subtype reveals their unique molecular signature.

Astrocytes are recognized to be a heterogeneous population of cells that differ morphologically, functionally, and molecularly. Whether this heterogeneity results from generation of distinct astrocyte cell lineages, each functionally specialized to perform specific tasks, remains an open question. In this study, we used RNA sequencing analysis to determine the global transcriptome profile of the Olig2-expressing astrocyte subtype (Olig2-AS), a specific spinal astrocyte subtype that segregates early during development from Olig2 progenitors and differs from other spinal astrocytes by the expression of Olig2.

Sulf2a controls Shh-dependent neural fate specification in the developing spinal cord.

Sulf2a belongs to the Sulf family of extracellular sulfatases which selectively remove 6-O-sulfate groups from heparan sulfates, a critical regulation level for their role in modulating the activity of signalling molecules. Data presented here define Sulf2a as a novel player in the control of Sonic Hedgehog (Shh)-mediated cell type specification during spinal cord development. We show that Sulf2a depletion in zebrafish results in overproduction of V3 interneurons at the expense of motor neurons and also impedes generation of oligodendrocyte precursor cells (OPCs), three cell types that depend on Shh for their generation.

Sulfatase 2 promotes generation of a spinal cord astrocyte subtype that stands out through the expression of Olig2.

Generation of glial cell diversity in the developing spinal cord is known to depend on spatio-temporal patterning programs. In particular, expression of the transcription factor Olig2 in neural progenitors of the pMN domain is recognized as critical to their fate choice decision to form oligodendrocyte precursor cells (OPCs) instead of astrocyte precursors (APs). However, generating some confusion, lineage-tracing studies of Olig2 progenitors in the spinal cord provided evidence that these progenitors also generate some astrocytes.