Competing endogenous RNAs act as molecular 'sponges.' What does this mean, and what do they compete with?

Verified step by step guidance

1. Understand that competing endogenous RNAs (ceRNAs) are RNA molecules that regulate gene expression by binding to microRNAs (miRNAs), which are small non-coding RNAs involved in gene silencing.
2. Recognize that miRNAs typically bind to messenger RNAs (mRNAs) to inhibit their translation or promote their degradation, thus reducing protein production.
3. Learn that ceRNAs act as molecular 'sponges' by containing binding sites for specific miRNAs, effectively sequestering these miRNAs and preventing them from binding to their target mRNAs.
4. Identify that the competition is between ceRNAs and mRNAs for binding to the same pool of miRNAs; by 'soaking up' miRNAs, ceRNAs reduce the miRNA-mediated repression of mRNAs.
5. Conclude that this mechanism allows ceRNAs to indirectly regulate gene expression by modulating the availability of miRNAs to their target mRNAs.

Key Concepts

Competing Endogenous RNAs (ceRNAs)

Competing endogenous RNAs are RNA molecules that regulate gene expression by binding and sequestering microRNAs (miRNAs). By acting as molecular 'sponges,' they reduce the availability of miRNAs to bind their usual target mRNAs, thus influencing the expression of those genes.

MicroRNAs (miRNAs)

MicroRNAs are small non-coding RNAs that regulate gene expression post-transcriptionally by binding to complementary sequences on target mRNAs, leading to mRNA degradation or translational repression. Their activity is modulated by interactions with ceRNAs.

Molecular 'Sponge' Mechanism

The 'sponge' mechanism refers to ceRNAs competing with mRNAs for binding to shared miRNAs. By sequestering miRNAs, ceRNAs prevent them from repressing target mRNAs, thereby indirectly increasing the expression of those genes.