Yan, Y.-T. | Search bioRxiv

bioRxiv2021

Chromatin state transition underlies the temporal changes in gene expression during cardiomyocyte maturation

Congenital heart disease (CHD) is often rooted in gene expression anomalies that occur during heart development. As cells commit to a specific lineage, chromatin dynamics and developmental plasticity generally become more limited. However, it remains unclear how differentiated cardiomyocytes (CMs) undergo morphological and functional adaptations to the postnatal environment during their maturation. In this work, we sought to identify the regulatory mechanisms controlling postnatal cardiac gene networks. A time-series transcriptomic analysis of postnatal hearts revealed an integrated, time-ordered transcriptional network that regulates CM maturation. Remarkably, depletion of histone H2B ubiquitin ligase RNF20 after formation of the four-chamber heart disrupted these highly coordinated gene networks. Its ablation also caused early-onset cardiomyopathy, a phenotype reminiscent of CHD. Furthermore, we found that dynamic RNF20-mediated modulation of chromatin accessibility during CM maturation was necessary for the operative binding of cardiac transcription factors known to drive transcriptional gene networks. Together, our results reveal how epigenetic-mediated chromatin state transitions modulate time-ordered gene expression during CM maturation.

developmental biology↗

bioRxiv2018

Repression of Dlx1/2 Signaling by Nolz-1/Znf503 is Essential for Parcellation of the Striatal Complex into Dorsal and Ventral Striatum

The division of the striatum into dorsal and ventral districts is of central clinical importance. The dorsal striatum is differentially affected in Huntingtons disease, dopamine in the ventral striatum is differentially spared in Parkinsons disease, and human brain imaging studies implicate the ventral striatum in addictive disorders. If fits that the dorsal striatum contains the cells of origin of the direct and indirect basal ganglia pathways for motor control. The ventral striatum is a node in neural circuits related to motivation and affect. Despite these striking neurobiologic contrasts, there is almost no information about how the dorsal and ventral divisions of the striatum are set up during development. Here, we demonstrate that interactions between the two key transcription factors Nolz-1 and Dlx1/2 control the migratory paths of developing striatal neurons to the dorsal or ventral striatum. Moreover, these same transcription factors control the cell identity of striatal projection neurons in both the dorsal and ventral striatum including the cell origin of the direct and indirect pathways. We show that Nolz-1 suppresses Dlx1/2 expression. Deletion of Nolz-1 or over-expression of Dlx1/2 can produce a striatal phenotype characterized by withered dorsal striatum and a swollen ventral striatum, and that we can rescue this phenotype by manipulating the interactions between Nolz-1 and Dlx1/2 transcription factors. This evidence suggests that the fundamental basis for divisions of the striatum known to be differentially vulnerable at maturity is already encoded by the time embryonic striatal neurons begin their migrations into the developing striatum.

neuroscience↗