CLEAR VISUALIZATION OF THE PRODUCTS OF NONRADIOACTIVE IN-SITU HYBRIDIZATION IN PLANT-TISSUE BY SIMPLE DARK-FIELD MICROSCOPY

Nonradioactive in situ hybridization is a powerful technique for deter mining levels of mRNA that have accumulated in tissues, and bright-hel d microscopy has been used extensively to detect signals generated by nonradioactive in situ hybridization. We converted an inverted microsc ope to a dark-field microscope by equipping it with a handmade ring-sl it. When the in situ hybridization pattern in a plant tissue was exami ned by this simple method of dark-field microscopy, the hybridization signals appeared clearly bluish-purple within the silvery white cell w alls of plant tissues. This method eliminates the necessity for counte rstaining because the silvery white cell walls clearly reveal the shap e of the plant tissues. Furthermore, color reproduction of processed i mages obtained by simple dark-field microscopy clearly reveals the sit es of expression of mRNA. (C) 1997 Elsevier Science Ltd.