5 Introduction to the Detection of Specific DNA and RNA Sequences
61
Amplification of HRp·DAB signal
Direct
ABC
CSA
Fig. 3. Remarkable enhancement of 285 rRNA signal by catalyzed signal amplification (CSA) (Koji et al. 1997). The frozen sections of rat brain fixed with 4%
paraformaldehyde in PBS were hybridized with a very low concentration of T -T
dimerized oligo-DNA complementary to rat 285 rRNA. In the immunohistochemical steps, the signal was detected by the different methods. In all methods,
the sites ofHRP were visualized according to Adams' method (1981). Top panel
(Direct): The signal was detected by the direct method with HRP-labeled anti(T-T dimer). The staining for 285 rRNA was barely detectable. Middle panel
(ABC): After hybridization, the signal was detected using the HRP- labeled avidin-biotin complex (ABC) method. The intensity of 28S rRNA signal was increased slightly but significantly. Bottom panel (CSA): After hybridization,
the section was reacted with HRP-labeled anti-(T-T dimer), biotinylated tyramine and HRP-labeled streptavidin, successively. Now the signal was very clear.
61
Amplification of HRp·DAB signal
Direct
ABC
CSA
Fig. 3. Remarkable enhancement of 285 rRNA signal by catalyzed signal amplification (CSA) (Koji et al. 1997). The frozen sections of rat brain fixed with 4%
paraformaldehyde in PBS were hybridized with a very low concentration of T -T
dimerized oligo-DNA complementary to rat 285 rRNA. In the immunohistochemical steps, the signal was detected by the different methods. In all methods,
the sites ofHRP were visualized according to Adams' method (1981). Top panel
(Direct): The signal was detected by the direct method with HRP-labeled anti(T-T dimer). The staining for 285 rRNA was barely detectable. Middle panel
(ABC): After hybridization, the signal was detected using the HRP- labeled avidin-biotin complex (ABC) method. The intensity of 28S rRNA signal was increased slightly but significantly. Bottom panel (CSA): After hybridization,
the section was reacted with HRP-labeled anti-(T-T dimer), biotinylated tyramine and HRP-labeled streptavidin, successively. Now the signal was very clear.