Biogenesis of piRNAs: A) piRNAs are generated from primary and second pathways (Ping-Pong cycle)
Biogenesis of piRNAs: A) piRNAs are generated from primary and second pathways (Ping-Pong cycle). In the primary pathway, piRNA precursors are transcribed from piRNA clusters. Antisense primary piRNAs are cleaved, trimmed to short fragments, and its 3’ ends are 2’-O-methylated and then loaded onto Piwi family proteins. In the secondary amplification pathways, also known as the Ping-Pong cycle, PIWI proteins associated with antisense piRNA and cleaves piRNA precursors in the sense strand, or PIWI proteins associated with sense piRNA and cleaves antisense piRNA precursors in the sense strand. The incorporated RNA is therefore processed into a mature secondary piRNA by trimming and modification likely by the same mechanisms that generated a primary piRNA. B) The biological functions of piRNAs. In the nucleus, Piwi-piRNAs complexes can repress transposon expression by methylation of transposon region or chromatin modification around transposon region. In the cytoplasm, piRNAs can degrade retrotransposon-associated mRNAs, cause cleavage of mRNAs through a miRNA-like mechanism and facilitate mRNA maturation.

Publication
Piwi-interacting RNAs (piRNAs) and Cancer: Emerging Biological Concepts and Potential Clinical Implications. (2019) Wenhao Weng, et al. Biochim Biophys Acta Rev Cancer. 2019 Jan;1871(1):160-169. Figure: F1.Organism | Group | Word | Match | Source | NCBI Symbol | NCBI ID |
---|---|---|---|---|---|---|
Drosophila melanogaster | Invertebrates | Zuc | ZUC | ncbigene_symbol | zuc | 34609 |
Drosophila melanogaster | Invertebrates | PIWI | PIWI | ncbigene_symbol | piwi | 34521 |
Drosophila melanogaster | Invertebrates | Hen1 | HEN1 | ncbigene_symbol | Hen1 | 36301 |
Drosophila melanogaster | Invertebrates | Sense | SENSE | ncbigene_synonym | sens | 45328 |
Drosophila melanogaster | Invertebrates | cycle | CYCLE | ncbigene_synonym | CycE | 34924 |
Drosophila melanogaster | Invertebrates | cycle | CYCLE | ncbigene_synonym | cyc | 40162 |
Drosophila melanogaster | Invertebrates | LINE-1,ALU... | ALU | ncbigene_symbol | Alu | 247748 |
Drosophila melanogaster | Invertebrates | (TES) | TES | ncbigene_symbol | Tes | 36965 |
Drosophila melanogaster | Invertebrates | (TES) | TES | ncbigene_synonym | Camta | 35974 |
Word | Match | MeSH | Name | ChEBI |
---|
Disease mentions
Word | Match | MeSH | Name | DOID |
---|