April 21, 2010

Ontogenesis is Regulated by Moving MicroRNA Molecules

The genes in humans and many other species have been surveyed but their operating principles remain rather unknown. Researchers do not know precisely how genes guide development of various human tissues, or what causes developmental disorders. MicroRNA molecules, are recently identified regulatory factors, whose on-going analysis, provide more insight into the matter.

This week, a team from the Institute of Biotechnology of the University of Helsinki, Duke University, Uppsala University and Boyce Thompson Institute will publish the latest results of their research in the journal Nature. The article introduces new information about this gene group, which is essential for the formation of structure of plants and animals.

MicroRNAs are small molecules that regulate the activity of other genes. They affect development and differentiation of tissues. MicroRNAs are negative regulators, which means they are also capable of stopping the operations of certain genes. Negative regulation is often important because if it is prevented, tumours, cancer and other developmental disorders may occur.

In a new study, Professor Yrjö Helariutta's team and colleagues show the key role of these molecules in chemical communication between plant cells. They showed that microRNAs are capable of moving from cell to cell, and conveying information between them. However, the research findings are universal, since besides plants, these molecules also appear in animal and human tissues, such as in brains.

Mutual communication between plant cells

The researchers described, in its entirety, a model where plants' different cells 'discuss' with each other. One cell layer sends a signal to another layer which replies to the first. In this way, cells know their place in the three-dimensional structure of the plant.

The researchers showed that microRNAs are synthesised in the cell's endodermic layer from where they move to the surrounding cells. This movement regulates how the cells within and outside the microRNA field will develop.

The findings can be applied generally to plant biology but also other fields, perhaps even medicine, and plant biology. It is possible that the microRNA molecules found in animals also move from cell to cell, establishing regulatory fields during development of human tissues, for example in the brain.


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