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Museridze, M.

Publications and source records attributed to Museridze, M..

3 recordsLinked to original sources

Trends in the representation of research on model organisms in scientific literature

Research using model organisms to tackle questions in life sciences and biomedical sciences has been in the spotlight of scientific literature for the better part of the twentieth century. This attention has perceptibly faded over the last twenty years, at least. We set to document this process by examining the publication trends of 48 journals encompassing a broad range of topics and impact factors for eight classic model organisms. We found that the representation of model-organism research has been in continuous decline in the last three decades, with a significant acceleration since 2010. We investigated the origin of the change, from the size of research communities to the shifts in topics and in use of model organisms. While model organism communities appear stable, model organism papers are outpaced by the rest of scientific literature. Also, among papers using model organisms, we note a progressive shift toward applied research, with differences between different model organism species. The mouse, in particular, logically remains the preferred system to study diseases, while non-mouse model organisms continue to be used predominantly to dissect mechanisms of life. We reflect on the consequences of the fading representation that we measured for the future of life sciences. Fundamentally, model organisms afford a direct access to causality in life sciences and their fading from the picture may impact life sciences as a whole. More pragmatically, it will also affect funding, and thereby jeopardizes the maintenance of model organism resources such as repositories built over decades.

scientific communication and education↗

Entangled and non-modular enhancer sequences producing independent spatial activities

The modularity of transcriptional enhancers (1, 2) is central to our understanding of morphological evolution, as it allows specific changes to a gene expression pattern component, without affecting others (3). Enhancer modularity refers to physically separated stretches of regulatory sequence producing discrete spatiotemporal transcriptional activity. This concept stems mainly from assays that test the sufficiency of a DNA segment (4) to drive spatial reporter expression resembling that of the corresponding gene. Focusing on sufficiency to produce spatial patterns, it overlooks quantitative aspects of gene expression, underestimating the regulatory sequence actually required to reach full endogenous expression levels. Here we show that five regulatory activities of the pigmentation gene yellow in Drosophila, classically described as modular (5-7), result from extensively overlapping sequences, with broadly distributed regulatory information. Nevertheless, the independent regulatory activities of these entangled enhancers appear to be nucleated by specific segments that we called enhancer cores. Our work calls for a reappraisal of enhancer definition and properties, as well as of the consequences on regulatory evolution.

developmental biology↗

Deciphering the regulatory logic of a Drosophila enhancer through systematic sequence mutagenesis and quantitative image analysis

Transcriptional enhancers are short DNA sequences controlling the spatial activity, timing and levels of eukaryotic gene transcription. Their quantitative transcriptional output is thought to result from the number and organization of transcription factor binding sites (TFBSs). Yet, how the various aspects of regulatory information are encoded in enhancer sequences remains elusive. We addressed this question by quantifying the spatial activity of the yellow spot enhancer active in developing Drosophila wings. To identify which enhancer DNA sequence contributes to enhancer activity, we introduced systematic mutations along the enhancer. We developed an analytic framework that uses comprehensive descriptors to quantify reporter assay in transgenic flies and measure spatial variations in activity levels across the wing. Our analysis highlights an unexpected density of regulatory information in the spot enhancer sequence. Furthermore, it reveals an unanticipated regulatory logic underlying the activity of this enhancer, and how it reads the wing trans-regulatory landscape to encode a spatial pattern.

genetics↗