Genetic Analysis of Protein Localization

Abstract

INTRODUCTION
Protein localization is the process by which a protein is exported from its site of synthesis in the cytoplasm to any one of a number of different cellular compartments. During the last decade, this aspect of cellular biogenesis has been the focus of considerable research. Despite obvious differences in the subcellular structure of prokaryotic and eukaryotic cells, all cells seem to use similar mechanisms of protein export. For example, experiments using recombinant DNA technology have shown that the intragenic information specifying export in a eukaryotic gene (ovalbumin, insulin) can be recognized by Escherichia coli and vice versa (alkaline phosphatase [PhoA]; β-lactamase [Bla]) (Fraser and Bruce 1978; Talmadge et al. 1980; Roggenkamp et al. 1981, Müller et al. 1982). This conservation of export mechanisms has fostered exchange of information among scientists working in areas as diverse as eukaryotic cell biology and prokaryotic molecular genetics.

In this paper we discuss the genetic techniques that have been applied successfully to the study of protein localization in E. coli. Because of its relative sophistication, genetic analysis in E. coli surpasses that currently possible with other systems. However, research in the field of protein localization is multidisciplinary, and other cells offer distinct advantages with respect to biochemical analysis. Therefore, to familiarize the reader with current concepts and unsolved problems, we begin by briefly reviewing the relevant biochemical data. For a more detailed account of these studies, the reader is referred to cited reviews.

PROTEIN LOCALIZATION IN EUKARYOTIC CELLS
The basic principles of protein export...