Immunogold labeling of yeast cells: an efficient tool for the study of protein targeting and morphological alterations due to overexpression and inactivation of genes.

Immunogold labeling on Lowicryl HM20 resin sections is a valuable complement to biochemical methods as well as methods of molecular biology in the study of basic mechanisms in the yeast system. This contribution presents an overview of the state of the art. Emphasis is put on the explanation of caveats and pitfalls rather than on detailed bench protocols. In the Applications section the morphological aspect of genetic manipulation is accentuated and links to human pathology are indicated. The morphological consequences of genetic manipulations may gain importance in view of the efforts made to establish gene therapies. In particular, the contribution of immunoelectron microscopy to the elucidation of peroxisomal targeting signals and to the detection and identification of morphological alteration due to overexpressed, mutated or deleted genes in the context of peroxisome biogenesis is described.