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.
Biogenesis of piRNAs: A) piRNAs are generated from primary and second pathways (Ping-Pong cycle)

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.

Gene mentions


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

Chemical mentions

Word Match MeSH Name ChEBI

Disease mentions

Word Match MeSH Name DOID