Eukaryotic Gene Expression Problem Set

Problem 9: Hybridization of mRNA with the DNA coding strand

mRNA will form hybrids only with the coding strand of DNA because:


DNA-RNA duplex molecule
An RNA molecule can form a base-paired DNA-RNA duplex molecule with a DNA that has complementary base pairing. The most common source of DNA complementary to an mRNA is the DNA coding strand that was the template for synthesis of the RNA. RNA-DNA hybridization follows the same base pairing rules as two complementary DNA strands. The two complementary strands have opposite polarity, i.e. a strand with 5' → 3' direction pairs with a complementary strand of opposite direction, 3' → 5'.

In DNA-RNA hybrid formation, G base pairs with C, A of the RNA pairs with T of the DNA, and U or the RNA pairs with A of the DNA. The DNA-RNA hybridization reaction is illustrated below:

The Biology Project
University of Arizona
Thursday, October 30, 1997
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