Argonaute and Piwi proteins are essential components of the RNA interference (RNAi) and small RNA pathways in eukaryotes, pathways which play roles in gene regulation and genome defence. Argonaute proteins are a family of RNA-binding proteins central to RNA interference pathways, including small interfering RNA (siRNA) and microRNA (miRNA) pathways. These proteins play critical roles in gene regulation by silencing or degrading target mRNAs. One of the primary functions of Argonaute proteins is to bind small RNA molecules, such as siRNAs and miRNAs. These small RNAs act to guide Argonaute to specific target mRNAs through homologous base-pairing interactions. Once bound, Argonaute carries out its silencing function through two main mechanisms. Firstly, in the case of siRNAs, Argonaute can cleave the target mRNA at a specific position complementary to the siRNA. This cleavage results in the degradation of the mRNA thereby preventing the translation of the corresponding protein. An example of this mechanism can be seen in antiviral defence in plants, where siRNAs derived from viral genomes guide Argonaute to degrade viral RNAs. Alternatively, in the miRNA pathway, Argonaute binding to the target mRNA does not usually lead to cleavage. Instead, it often results in translational repression or degradation of the mRNA. An example is the regulation of the let-7 miRNA family in controlling developmental timing in C. elegans. The let-7 miRNA targets specific mRNAs involved in development, and Argonaute binding inhibits their translation. Argonaute proteins can be involved in other pathways besides RNAi. For example, in some cases, they play a role in maintaining genome stability by guiding the formation of heterochromatin, the condensed and transcriptionally inactive form of chromatin. In fission yeast, Argonaute proteins are involved in the formation of heterochromatin at repetitive DNA sequences. Piwi proteins are a distinct class of Argonaute proteins expressed mainly in germline cells. They are involved in a pathway known as the piRNA (piwi-interacting RNA) pathway. PiRNAs are a class of small RNAs primarily expressed in the germline and essential for maintaining genome integrity and inhibiting transposon mobility. Transposons can move within the genome and disrupt gene function. Piwi proteins, guided by piRNAs, target and silence transposon sequences by cleaving or epigenetically modifying them. This mechanism is important for preventing genome instability and maintaining germ cell integrity. For example, in Drosophila Piwi-piRNA complexes silence transposons during oogenesis. Piwi-piRNA complexes can also establish epigenetic modifications, such as DNA methylation and histone modifications, at transposon loci. This leads to long-term silencing of transposons and contributes to genome stability. For example, in mice Piwi-piRNA complexes are involved in DNA methylation and silencing of transposons during spermatogenesis. Thus, Argonaute and Piwi proteins mediate RNA interference pathways, with Argonaute proteins involved in siRNA and miRNA pathways for gene regulation, whilst Piwi proteins specialize in the piRNA pathway for transposon silencing and genome stability maintenance in germline cells. We provide a large product range of research reagents for investigating Argonaute and Piwi, including Dcp1a antibodies, and PIWIL1 antibodies. Explore our full Argonaute and Piwi product range below and discover more, for less.