Switched on by gene kisses

Pretoria - Local scientists have made a groundbreaking discovery, proving that when genes interact in three dimensions, so-called “gene kissing”, there is a major impact on how genes are switched on inside the cell. A long-standing question in biology is whether gene kissing is a cause – or simply correlated – with gene activation. This question was finally answered when a team led by Dr Musa Mhlanga, CSIR gene expression and biophysics research group leader, and a collaborator at Wits University, performed experiments to show that gene kissing can switch genes on.

The discovery sheds light on how genes change from inactive to active states, and how different genes can co-ordinate their activity simultaneously.

Mhlanga is passionate about what this discovery means.

Within each human cell lies 1.2m of tightly coiled DNA, shrunk to one-fiftieth the size of a grain of sand.

These genes encode our physical traits, such as eye colour or blood type. However, DNA also codes for genes that function constantly to keep us alive. These need to be switched “on” and “off” by the cell as needed.

“DNA is coiled and tangled like spaghetti inside the cell,” explains Professor Marc Weinberg from Wits and co-author of the study.

“So, there are many places where the DNA touches and intersects. These interactions could be crucial to how the information in the DNA is read and interpreted by the cell, but this had never been shown before.”

The team used state-of-the-art microscopes they built themselves. These tools enabled them to see the activity of even a single gene, among 30 000.

Using DNA nucleases – nicknamed “molecular scissors” – they were able to cut DNA at precise locations to prevent genes from making contact.

According to lead author, Dr Stephanie Fanucchi, “being able to alter the genetic code in this manner is the ‘holy grail’ of molecular biology, but has only recently been made possible”.

In this way, some genes were shown to “kiss” in order to be switched “on” and, surprisingly in this instance, one gene acts as a master gene to orchestrate the activity of other genes.

The group is focusing some of its efforts on what this work could mean for human health.

Scientists will gain a deeper understanding of cancer, diabetes, allergy responses and a host of other diseases and important cellular processes.

Mhlanga is passionate about what this discovery means: “This work germinated from a desire to answer a fundamental question in gene regulation.

“Our goal is that scientists in Africa should not simply be consumers of fundamental scientific discoveries; rather they should be active contributors and producers to this body of knowledge.”

The landmark finding appears in Thursday’s issue of the journal Cell. - Pretoria News