An insulator embedded in the chicken α-globin locus regulates chromatin domain configuration and differential gene expression

Genome organization into transcriptionally active domains denotes one of the first levels of gene expression regulation. Although the chromatin domain concept is generally accepted, only little is known on how domain organization impacts the regulation of differential gene expression. Insulators might hold answers to address this issue as they delimit and organize chromatin domains. We have previously identified a CTCF-dependent insulator with enhancer-blocking activity embedded in the 5′ non-coding region of the chicken α-globin domain. Here, we demonstrate that this element, called the αEHS-1.4 insulator, protects a transgene against chromosomal position effects in stably transfected cell lines and transgenic mice. We found that this insulator can create a regulated chromatin environment that coincides with the onset of adult α-globin gene expression. Furthermore, such activity is in part dependent on the in vivo regulated occupancy of CTCF at the αEHS-1.4 element. Insulator function is also regulated by CTCF poly(ADP-ribosyl)ation. Our results suggest that the αEHS-1.4 insulator contributes in organizing the chromatin structure of the α-globin gene domain and prevents activation of adult α-globin gene expression at the erythroblast stage via CTCF

Using “omics” and integrated multi-omits approaches to guide probiotic selection to mitigate chytridiomycosis and other emerging infectious diseases

Emerging infectious diseases in wildlife are responsible for massive population declines. In amphibians, chytridiomycosis caused by Batrachochytrium dendrobatidis, Bd, has severely affected many amphibian populations and species around the world. One promising management strategy is probiotic bioaugmentation of antifungal bacteria on amphibian skin. In vivo experimental trials using bioaugmentation strategies have had mixed results, and therefore a more informed strategy is needed to select successful probiotic candidates. Metagenomic, transcriptomic, and metabolomic methods, colloquially called “omics,” are approaches that can better inform probiotic selection and optimize selection protocols. The integration of multiple omic data using bioinformatic and statistical tools and in silico models that link bacterial community structure with bacterial defensive function can allow the identification of species involved in pathogen inhibition. We recommend using 16S rRNA gene amplicon sequencing and methods such as indicator species analysis, the Kolmogorov–Smirnov Measure, and co-occurrence networks to identify bacteria that are associated with pathogen resistance in field surveys and experimental trials. In addition to 16S amplicon sequencing, we recommend approaches that give insight into symbiont function such as shotgun metagenomics, metatranscriptomics, or metabolomics to maximize the probability of finding effective probiotic candidates, which can then be isolated in culture and tested in persistence and clinical trials. An effective mitigation strategy to ameliorate chytridiomycosis and other emerging infectious diseases is necessary; the advancement of omic methods and the integration of multiple omic data provide a promising avenue toward conservation of imperiled species

Preparing for a Bsal invasion into North America has improved multi-sector readiness

Western palearctic salamander susceptibility to the skin disease caused by the amphibian chytrid fungus Batrachochytrium salamandrivorans (Bsal) was recognized in 2014, eliciting concerns for a potential novel wave of amphibian declines following the B. dendrobatidis (Bd) chytridiomycosis global pandemic. Although Bsal had not been detected in North America, initial experimental trials supported the heightened susceptibility of caudate amphibians to Bsal chytridiomycosis, recognizing the critical threat this pathogen poses to the North American salamander biodiversity hotspot. Here, we take stock of 10 years of research, collaboration, engagement, and outreach by the North American Bsal Task Force. We summarize main knowledge and conservation actions to both forestall and respond to Bsal invasion into North America. We address the questions: what have we learned; what are current challenges; and are we ready for a more effective reaction to Bsal’s eventual detection? We expect that the many contributions to preemptive planning accrued over the past decade will pay dividends in amphibian conservation effectiveness and can inform future responses to other novel wildlife diseases and extreme threats