Nolte, C. | bioRxiv Science

bioRxiv2022

Shared retinoic acid responsive enhancers coordinately regulate nascent transcription of Hoxb coding and non-coding RNAs in the developing mouse neural tube

Signaling pathways regulate the patterns of Hox gene expression that underlie their functions in specification of axial identity. Little is known about the properties of cis-regulatory elements and underlying transcriptional mechanisms that integrate graded signaling inputs to coordinately control Hox expression. Here we optimized single molecule fluorescent in situ hybridization (smFISH) technique with probes spanning introns to evaluate how three shared retinoic acid response element (RARE)-dependent enhancers in the Hoxb cluster regulate patterns of nascent transcription in vivo at the level of single cells in wild type and mutant embryos. We predominately detect nascent transcription of only a single Hoxb gene in each cell, with no evidence for simultaneous co-transcriptional coupling of all or specific subsets of genes. Single and/or compound RARE mutations indicate each enhancer differentially impacts global and local patterns of nascent transcription, suggesting that selectivity and competitive interactions between these enhancers is important to robustly maintain the proper levels and patterns of nascent Hoxb transcription. This implies rapid and dynamic regulatory interactions potentiate transcription of genes through combined inputs from these enhancers in coordinating the RA response.

developmental biology↗

bioRxiv2021

Delivering on Biden's 2030 conservation commitment

On January 27, 2021, President Biden signed an executive order, Tackling the Climate Crisis at Home and Abroad, committing the United States to various goals within his campaigns major climate policy, the Biden Plan for a Clean Energy Revolution and Environmental Justice. Included in this executive order is a commitment to "conserving at least 30 percent of [the United States] lands and oceans by 2030." This ambitious conservation target signals a promising direction for biodiversity in the United States. However, while the executive order outlines several goals for climate mitigation, the 30x30 target remains vague in its objectives, actions, and implementation strategies for protecting biodiversity. Biodiversity urgently needs effective conservation action, but it remains unclear where and what this 30% target will be applied to. Achieving different climate and biodiversity objectives will require different strategies and, in combination with the associated costs of implementation, will lead to different priority areas for conservation actions. Here, we illustrate what the 30% target could look like across four objectives reflective of the ambitious goals outlined in the executive order. We compile several variations of terrestrial protected area networks guided by these different objectives and examine the trade-offs in costs, ecosystem representation, and climate mitigation potential between each. We find little congruence in priority areas across objectives, emphasizing just how crucial it will be for the Biden administration to develop clear objectives and establish appropriate performance metrics from the outset to maximize both conservation and climate outcomes in support of the 30x30 target. We discuss important considerations that must guide the administrations conservation strategies in order to ensure meaningful conservation outcomes can be achieved over the next decade.

ecology↗