#myofibrils

Shooting Messengers

In a hurry for a train, stretchy regions in our leg muscles called sarcomeres contract and expand to pull our bones along. Zooming in further on this mouse muscle, scientists follow molecules on their own journey – messenger RNAs (highlighted in red) are carrying genetic information, used as templates to build proteins. A technique called RNA FISH, spots RNAs travelling from the muscle fibre’s nuclei (where they’re made) to z-disks (blue) at the boundaries between sarcomeres along a muscle myofibre. The RNAs zip along the muscle’s network of microtubules (green) like tube or metro lines (although a billion times smaller). Scientists see patterns of different RNAs at the z-disks, clustering like cosmopolitan crowds of commuters at train stations – perhaps as a way to spread a variety of useful proteins along our muscles, which may be disrupted in myopathies.

Written by John Ankers

Image from work by Lance T. Denes, Chase P. Kelley & Eric T. Wang

Department of Molecular Genetics & Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA

Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in Nature Communications, October 2021

Hippo with Wings

Muscles are incredibly complex structures made up of long fibres, each up to several centimetres in length and packed with tiny strings known as myofibrils, which contract to generate muscular force. Building such complicated structures as an embryo grows into an animal is no easy task, so researchers are studying fruit fly wing muscles to figure out exactly which genes are involved and how they all work together. Some of the most important players are a group of genes that collectively form what’s known as the Hippo pathway: a series of interacting processes that control cell growth in many animals, including humans. These microscope images show muscles from fruit flies with various alterations in a key gene in the Hippo pathway known as Yorkie. Understanding how Yorkie and its partners work in muscle growth in flies helps to shed light on what’s going on during human muscle development and disease.

Written Kat Arney

Image adapted from work by Aynur Kaya-Çopur and colleagues

Aix Marseille University, CNRS, IBDM, Turing Center for Living Systems, Marseille, France

Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in eLife, January 2021