In this chapter, we focused on how eukaryotic gene expression is regulated posttranscriptionally. At the same time, we found many opportunities to consider the methods and reasoning by which much of this information was acquired. From the explanations given in the chapter:

How do we know that microRNAs negatively regulate target mRNAs?

Key Concepts

MicroRNAs (miRNAs)

MicroRNAs are small, non-coding RNA molecules that play a crucial role in regulating gene expression. They typically bind to complementary sequences on target messenger RNAs (mRNAs), leading to mRNA degradation or inhibition of translation. This posttranscriptional regulation is essential for controlling various biological processes, including development, differentiation, and response to environmental changes.

Target mRNAs

Target mRNAs are the specific messenger RNAs that are regulated by microRNAs. The interaction between miRNAs and their target mRNAs is determined by sequence complementarity, which allows miRNAs to selectively bind and modulate the expression of genes. Understanding which mRNAs are targeted by specific miRNAs is vital for elucidating the regulatory networks that govern cellular functions.

Experimental Evidence

The assertion that microRNAs negatively regulate target mRNAs is supported by various experimental approaches, such as reporter assays, gene knockout studies, and RNA sequencing. These methods demonstrate that the presence of specific miRNAs leads to decreased levels of their target mRNAs, either through degradation or translational repression, thereby providing a clear link between miRNA activity and gene expression regulation.