Control of Gene Expression

Dr. Brian Miki, Study Leader

Objectives

1. To elucidate the diverse molecular mechanisms that control and influence patterns and levels of gene expression.

2. To manipulate or adapt them for controlling the expression of cloned genes in transgenic plants.

Rationale

The final location and quantity of a gene product within a multicellular organism, such as a higher plant, results from a cascade of individual biochemical events. Each step is governed by a separate regulatory mechanism. The coordination of each of them is needed to ensure the predictability of gene expression patterns and the homeostasis that is required for the survival of the organism. Research dealing with the control of gene expression is often focussed on the initiation of transcription or translation; however, it is recognized that many other processes such as signal transduction, protein trafficking and protein folding are vital for controlling the patterns of expression observed for any gene.

The broad goals of this study are to:

• generate novel information on these individual mechanisms,

• determine which steps are amenable to manipulation using molecular genetics,

• to assess whether the mechanisms are transferable to cloned genes for expression in transgenic plants, and

• to demonstrate utility in modifying traits in crops using cloned genes.

The control of expression of cloned genes is vital for the development of transgenic crops with novel traits. The worldwide genomics initiatives have resulted in the cloning of most plant genes and many of those from other organisms. To utilize these genes in transgenic crops it is essential to reconstruct them with gene regulatory elements to achieve the expression patterns required for the target phenotypes. At this time there are no tested gene regulatory elements that are in the public domain and that can be used freely to develop proprietary germplasm. All existing transgenic plants that are being grown in Canada are dependent on a limited number of expression systems that are patented by and controlled by industry. Despite the narrow base of gene expression technology being practiced the potential for exploiting unexplored yet fundamental processes involved in control of gene expression is enormous.

This study is developing novel gene regulatory elements and systems for controlling transcription and translation with desirable spatial and developmental characteristics that can be used in a variety of crops. The research is ensuring that the systems will integrate with the complex cascade of events that govern the final patterns of expression of the gene products.