In Situ Hybridization to Plant Tissue Sections

An important step in the analysis of gene action is to determine the spatial and temporal regulation of gene expression. The patterns of gene expression can provide clues to the function of genes and facilitate the mapping of qualitative changes in steady state mRNA levels. In situ hybridization is a cytochemical procedure first used to map sequences on chromosomes (1 ,2 ). It is also used to identify viral RNA in and around infection sites (3 ,4 ) and is commonly used for locating specific mRNA transcripts in tissue sections (5 –9 ). The technique can also be adapted for ultrastructural resolution particularly with biotin labeled probes (10 ,11 ).