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

Competing endogenous RNAs (ceRNAs) are a type of regulatory RNA molecule found in cells. They play a crucial role in gene expression and regulation by competing for shared microRNA (miRNA) binding sites.

The term "molecular sponge" is used to describe the function of ceRNAs because they can "soak up" miRNAs, preventing them from binding to their target messenger RNAs (mRNAs). By doing so, ceRNAs can modulate the expression of multiple target genes simultaneously. This also indirectly affects the stability and translation of target mRNA molecules.

Competing endogenous RNAs (ceRNAs) compete with other RNA molecules, such as messenger RNAs (mRNAs) and long noncoding RNAs (lncRNAs), for the binding of shared microRNA (miRNA) response elements (MREs). By sequestering miRNAs from their target mRNAs, ceRNAs can indirectly regulate gene expression levels by affecting mRNA stability and translation. This competition helps to fine-tune and maintain the balance of gene expression within a cell. In summary, competing endogenous RNAs (ceRNAs) act as molecular "sponges" by sequestering miRNAs and preventing them from binding to target mRNA molecules. This results in the modulation of gene expression levels. The competition of ceRNAs occurs with other RNA molecules, such as mRNAs and lncRNAs, for shared miRNA binding sites.