Reporter Gene Systems for Halophilic Microorganisms

Abstract

The technological ability to follow and understand how and when genes are turned on, how gene products reach their final target, how cells respond to chemical changes in their environment and how cells manage to communicate with each other is indispensable for modern biological research in all living systems. In the post-genomics era the number of identified coding sequences with functions not easy to assay increases exponentially making their study an extremely difficult task. In this respect, the availability of reporter genes for virtually any organism has become an important genetic tool. Additionally, gene reporters have many applications in tagging of biotechnologically important microorganisms for environmental risk assessments. The use of a gene with an easily identifiable product to follow the expression of another gene was first applied some 30 years ago but only in the last decade has this become a widely used approach in gene expression and other tracing studies. Today, various genes have been used as reporters in representative organisms of all domains of the phylogenetic tree and for a wide variety of gene studies and applications (Jain 1996; Groskreutz and Schenborn 1997; Schenborn and Groskreutz 1999). Genes are suitable to be used as reporters only if they can express in their new host, their product can be readily assayed and their presence is not masked from native homologous activities. This chapter focuses on the recent advances in the development of gene reporter systems in halophilic bacteria and archaea. There are no reports as yet regarding halophilic eucaryotic microorganisms.