Using this novel approach, the researchers can view genes as they interact with each other. Noma and his colleagues can view where highly active genes are located, or see if genes that are turned on and off together also reside near each other in the three-dimensional structure of the genome. In total, the Wistar researchers also studied 465 so-called gene ontology groups groups of genes that share a related purpose in the cell, such as structure or metabolism.
"When the chromosomes come together, they fold into positions that bring genes from different chromosomes near each other," Noma said. "This positioning allows the processes that dictate how and when genes are read to operate efficiently on multiple genes at once."
This structure is not merely an accident of chemical attractions within and among the chromosomes although that is certainly a part of the larger whole but an arrangement guided by other molecules in the cell to create a mega-structure that dictates genetic function, Noma says. He envisions a scenario where accessory molecules, such as gene-promoting transcription factors, bind to DNA and contribute to the ultimate structure of the genome as the chromosomes fold together.
"I believe we are looking at a new way to visualize both the genome itself and the movements of all the various molecules that act on the genome," Noma said.
According to the Wistar scientists, their techniques are scalable to the human genome, even though fission yeast only has three chromosomes. In fact, the researchers found signs of "transcription factories" clusters of related genes that are read, or "transcribed," at discrete sites which have been proposed to exist in mammals.
|Contact: Greg Lester|
The Wistar Institute