What technique was used to characterize the distribution of ASBT mRNA?

• A. Immunohistochemistry
• B. qPCR
• C. RNA in situ hybridization
• D. Western blot

Answer: (C)

Mapping where ASBT mRNA is expressed within tissue requires a method that preserves tissue structure and shows the exact location of the transcript. RNA in situ hybridization uses labeled probes that bind specifically to ASBT mRNA in fixed tissue sections, producing a signal right at the cells and even subcellular areas where the transcript is present. This provides direct spatial information about expression, showing which cells and regions express ASBT.

In contrast, immunohistochemistry detects the protein product, not the mRNA, so it doesn’t reveal where the message is located. qPCR quantifies how much ASBT mRNA is present but requires destroying the tissue and homogenizing it, which eliminates any information about where the mRNA is distributed. Western blot similarly reports protein levels without any spatial context.RNA in situ hybridization uniquely answers the distribution question by visualizing the transcript itself in its native tissue context.