Collective behaviour, RAS and DNA repair, Semaphorin’s role in reproduction: this week in PLOS Biology
- Systems biology looks at the big picture of complex interactions within biological systems; one example is collective behaviour, where a system comprising multiple entities operates with no centralised control. Examples of this can be seen from the cellular level (groups of patrolling immune cells on the prowl for pathogens) to groups of animals (birds flying in flocks that turn in the sky in perfect synchrony). In an Essay this week Deborah Gordon describes how environmental constraints (such as operating costs) may have shaped the evolution of collective behaviour. She argues that similar evolutionary pressures have produced similar collective behaviour in groups from molecules to cells to whole animals. Ants are used here as an example, as a large, diverse and extremely successful taxon that is well known for its collective behaviour.
- A mark of a cancerous tumour is unregulated cell growth, potentially involving damage to the DNA of the cancer cells. However, in order to be successful and proliferate, cancer cells need to avoid the resulting senescence. In a Research Article this week, Alain Nepveu and colleagues identify a alternative workaround – the presence of an oncogenic ‘RAS’ gene heightens the ability of cells to repair damage to their DNA (specifically targeting the type of damage caused by oxidative stress).
- The semaphorins are a group of proteins present in cell membranes and responsible for diverse signalling functions. During the development of an embryo, they guide the development of blood vessels and neurons. However, whether these proteins continue to have any effects in the adult brain has been unclear. A new study by Paolo Giacobini, Vincent Prevot and colleagues suggests they do have a role: in mice they seem to be involved the essential regulation of reproduction – semaphorin molecules secreted by endothelial cells control axon growth and promote the timely release of a key hormone called Gonadotropin-releasing hormone (GnRH).