In:
eLife, eLife Sciences Publications, Ltd, Vol. 3 ( 2014-10-14)
Abstract:
Mitochondria are the main source of energy for cells. These vital and highly dynamic organelles continually change shape by fusing with each other and splitting apart to create new mitochondria, repairing and replacing those damaged by cell stress. For nerve impulses to be transmitted across the gaps (called synapses) between nerve cells, mitochondria need to supply the very ends of the nerve fibers with energy. To do this, the mitochondria must be transported from the main body of the nerve cell to the tips of the nerve fibers. This may not happen if mitochondria are the wrong shape, size or damaged. While searching for genetic mutations that disrupt nerve function in the fruit fly Drosophila, Sandoval et al. spotted mutations in a gene called Marf. Further investigations revealed that flies with mutant versions of Marf have small, round mitochondria, and their nerves cannot transmit signals to muscles when they are highly stimulated. This is because the mutant mitochondria are not easily transported along nerve fibers, and so not enough energy is supplied to the synapses. The synapses of the Marf mutants are also abnormally shaped. Sandoval et al. found that this is not because Marf is lost in the neurons themselves, but because it is lost from a hormone-producing tissue called the ring gland. Another problem found in flies with mutated Marf genes is that they stop developing while in their larval stage. Sandoval et al. established that this could also be related to the loss of Marf from the ring gland. The Marf protein has two different functions in the ring gland: forming and storing droplets of fatty molecules used in hormone production, and synthesising a hormone that controls when a fly larva matures into the adult fly. This suggests that the lower levels of this hormone produced by Marf mutant flies underlies their prolonged larval stages and synapse defects. Vertebrates (animals with backbones, such as humans) have two genes that are related to the fly's Marf gene. When the human forms of these genes were introduced into mutant flies that lack a working copy of Marf, hormone production was only restored if both genes were introduced together. This indicates that these genes have separate roles in vertebrates, but that these roles are both performed by the single fly gene. The role of Marf in tethering mitochondria in the ring gland may allow us to better understand how this process affects hormone production and how the different parts of the cell communicate.
Type of Medium:
Online Resource
ISSN:
2050-084X
DOI:
10.7554/eLife.03558.001
DOI:
10.7554/eLife.03558.002
DOI:
10.7554/eLife.03558.003
DOI:
10.7554/eLife.03558.004
DOI:
10.7554/eLife.03558.005
DOI:
10.7554/eLife.03558.006
DOI:
10.7554/eLife.03558.007
DOI:
10.7554/eLife.03558.008
DOI:
10.7554/eLife.03558.009
DOI:
10.7554/eLife.03558.010
DOI:
10.7554/eLife.03558.011
DOI:
10.7554/eLife.03558.012
DOI:
10.7554/eLife.03558.013
DOI:
10.7554/eLife.03558.014
DOI:
10.7554/eLife.03558.015
DOI:
10.7554/eLife.03558.016
DOI:
10.7554/eLife.03558.017
DOI:
10.7554/eLife.03558.018
DOI:
10.7554/eLife.03558.019
DOI:
10.7554/eLife.03558.020
DOI:
10.7554/eLife.03558.021
DOI:
10.7554/eLife.03558.022
DOI:
10.7554/eLife.03558.023
Language:
English
Publisher:
eLife Sciences Publications, Ltd
Publication Date:
2014
detail.hit.zdb_id:
2687154-3