Page "MicroRNA" Paragraph 4

The first miRNAs were characterized in the early 1990s.

However, miRNAs were not recognized as a distinct class of biological regulators with conserved functions until the early 2000s.

Since then, miRNA research has revealed multiple roles in negative regulation ( transcript degradation and sequestering, translational suppression ) and possible involvement in positive regulation ( transcriptional and translational activation ).

By affecting gene regulation, miRNAs are likely to be involved in most biological processes.

Different sets of expressed miRNAs are found in different cell types and tissues.