Argonautecontaining

Argonautecontaining refers to proteins or molecular complexes that include Argonaute (Ago) family members, which play a central role in RNA-guided gene regulation. Argonaute proteins are found in most branches of life and form the core of silencing systems that use small nucleic acids to control gene expression or defend against foreign genetic elements.

In eukaryotes, Argonaute proteins are the key component of RNA-induced silencing complexes (RISCs). They bind small RNAs such as microRNAs, small interfering RNAs, or PIWI-interacting RNAs and use the guide strand to recognize complementary target RNAs. Depending on the Ago and the pathway, the complex can cleave the target RNA or repress its translation and stability. A catalytic site in the PIWI domain—often a D-D-H triad—confers endonuclease “slicer” activity in some Ago proteins, while other Ago family members are catalytically inactive and act primarily through repression mechanisms. The PAZ and MID domains help position the guide RNA, binding the 3' and 5' ends respectively.

In prokaryotes, Argonaute proteins (pAgos) are more diverse in their architecture and function. Some use DNA guides to target DNA, others can use RNA guides, and their roles are often linked to defense against invasive genetic elements such as plasmids and phages. The functional diversity of pAgos makes them a focus of research for potential biotechnological applications, including programmable nucleases and novel gene-regulation tools.

Overall, Argonautecontaining proteins are a widespread and evolutionarily conserved family that enables RNA- and DNA-guided control of nucleic acids, with significant implications for biology and biotechnology.