On the use of regulatory regions from pigmentary genes to drive the expression of transgenes in mice

Abstract

The combination of known regulatory regions from mammalian genes and the coding regions of exogenous genes has been instrumental for the generation and analysis of transgenic mice and influences the resulting expression pattern in specific cells or tissues. The transgenes can be of prokaryotic (lacZ, CRE) or eukaryotic origin. The proteins encoded by these genes might or might not have functions interfering directly with the biology of the cell. They can be used as a direct molecular reporter (such as lacZ, for its enzymatic activity), as a direct cellular reporter (such as diphtheria toxin-A for genetic ablation experiments) or as an indirect molecular marker (such as the bacteriophage P1-derived site-specific recombinase Cre, to be used for CRE/loxP recombination strategies).

However, it is also known that the artificial combination of some regulatory regions of a given gene, fused with the coding region of for example a reporter gene, can give rise to unexpected sites of expression in transgenic animals, which are not reproduced by the known expression pattern of the endogenous gene (Fig. 1). While recognizing the potential use of these ectopic patterns, this should be carefully taken into consideration before using the reporter transgenic lines in subsequent experiments.