Biology subjects

Eichner, N.

Publications and source records attributed to Eichner, N..

3 recordsLinked to original sources

bioRxiv2023

Darwin's "neuters" and the evolution of the sex continuum in a superorganism

Ant castes are an amazing example of phenotypic plasticity. In worker-destined embryos of the ant Cardiocondyla obscurior, the default female developmental trajectory is interrupted even before the gonadal precursor cells acquire a sexual identity. miRNA and mRNA expression in embryos reveal three distinct phenotypic entities: males, females, and "neuters", as Darwin coined the worker caste in "On the Origin of Species". Based on these results we propose that haplodiploidy, in conjunction with insect sex determination, allows for the expression of a third dimension on the sex continuum, thus facilitating the evolution of individuals which develop traits their parents do not have. One sentence summarySex and caste differentiation begin during the same embryonic developmental window in the ant Cardiocondyla obscurior.

evolutionary biology↗

bioRxiv2023

In vivo AGO-APP identifies a module of microRNAs cooperatively controlling exit from neural stem cell state

MicroRNAs (miRNAs) are essential regulators of all developmental processes. Their function is particularly important during neurogenesis, when the production of large numbers of neurons from a limited number of neural stem cells depends on the precise control of determination, proliferation and differentiation. However, miRNA regulation of target mRNAs is highly promiscuous, one miRNA can target many mRNAs and vice versa, raising the question of how specificity is achieved to elicit a precise regulatory response. Here we introduce AGO-APP, a novel approach to purify Argonaute-bound miRNAs directly from cells and tissues in vivo, to isolate actively inhibiting miRNAs from different neural cell populations in the larval Drosophila central nervous system. We identify a defined group of miRNAs that redundantly target all iconic genes known to control the transition from neuroblasts to neurons. In vivo functional studies demonstrate that knockdown of individual miRNAs does not induce detectable cellular phenotypes. However, simultaneous knockdown of multiple miRNAs leads to precocious stem cell differentiation, demonstrating functional interdependence. Thus, miRNAs cooperate within a regulatory module to specify the targeted gene network.

developmental biology↗

bioRxiv2022

A rapid protocol for ribosome profiling of low input samples

Ribosome profiling provides quantitative, comprehensive, and high-resolution snapshots of cellular translation by the high-throughput sequencing of short mRNA fragments that are protected from nucleolytic digestion by ribosomes. While the overall principle is simple, the workflow of ribosome profiling experiments is complex and challenging, and typically requires large amounts of sample, limiting its broad applicability. Here, we present a new protocol for ultra-rapid ribosome profiling from low-input samples. It features a robust strategy for sequencing library preparation within one day that employs solid phase purification of reaction intermediates, allowing to reduce the input to as little as 0.1 pmol of RNA. Hence, it is particularly suited for the analyses of small samples or targeted ribosome profiling. Its high sensitivity and its ease of implementation will foster the generation of higher quality data from small samples, which opens new opportunities in applying ribosome profiling.

systems biology↗