Search results for PIWIL1

Showing 13 results out of 13

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Protein (1 results from a total of 1)

Identifier: R-HSA-5601891
Species: Homo sapiens
Compartment: cytosol
Primary external reference: UniProt: PIWIL1: Q96J94

Reaction (4 results from a total of 4)

Identifier: R-HSA-5615682
Species: Homo sapiens
Compartment: cytosol
After cleavage by PLD6 at the 5' end, the pre-piRNA is bound by PIWIL1 (HIWI, homolog of MIWI in mouse), likely in a complex with other proteins such as TDRD6 and TDRKH, which interact with methylated arginine residues on PIWIL1 and are required for piRNA biogenesis. Binding by PIWIL1 is believed to be selective for pre-piRNAs that have uracil residues at their 5' ends.
Identifier: R-HSA-5629203
Species: Homo sapiens
Compartment: cytosol
As inferred from mouse homologs, HENMT1 transfers a methyl group from S-adenosylmethionine to the 2' hydroxyl group of a trimmed piRNA bound by the PIWIL1 complex in the cytosol.
Identifier: R-HSA-5601888
Species: Homo sapiens
Compartment: cytosol
As inferred from mouse homologs, after binding PIWIL1 (HIWI in human, Miwi in mouse) the 3' end of the pre-piRNA is trimmed by an unknown nuclease. The final size of the piRNA appears to be determined by the particular PIWI protein with which it is associated. PIWIL1 and TDRD6 are located in the chromatoid body. Both TDRD6 and TDRKH are associated with PIWIL1 in adult testes but only TDRKH is present in embryonic prospermatogonia. TDRKH is required for spermatogenesis and appears to participate in trimming of the 3' end of pre-piRNAs.
Identifier: R-HSA-5601887
Species: Homo sapiens
Compartment: cytosol, mitochondrial outer membrane
As inferred from homologs in Drosophila and mouse, PLD6 (MitoPLD) located on the cytoplasmic face of the mitochondrial outer membrane makes the first endonucleolytic cleavage of primary piRNA transcripts. The cleavage yields a 5' phosphate and a 3' hydroxyl. Cleavage is believed to precede loading into PIWIL1 (HIWI, MIWI) or PIWIL2 (HILI, MILI). Most mature piRNAs have uracil at the 5' end. This appears to be due to selective binding by PIWI proteins rather than selective cleavage (reviewed in Bortvin 2013).

Complex (7 results from a total of 7)

Identifier: R-HSA-5629229
Species: Homo sapiens
Compartment: cytosol
Identifier: R-HSA-5629240
Species: Homo sapiens
Compartment: cytosol
Identifier: R-HSA-5601893
Species: Homo sapiens
Compartment: cytosol
Identifier: R-HSA-5601902
Species: Homo sapiens
Compartment: cytosol
Identifier: R-HSA-5603053
Species: Homo sapiens
Compartment: cytosol
Identifier: R-HSA-5603054
Species: Homo sapiens
Compartment: cytosol
Identifier: R-HSA-5603059
Species: Homo sapiens
Compartment: cytosol

Pathway (1 results from a total of 1)

Identifier: R-HSA-5601884
Species: Homo sapiens
In germ cells of humans and mice, precursors of PIWI-interacting RNAs (piRNAs) are transcribed from a few hundred sequence clusters, as well as individual transposons, intergenic regions, and genes in the genome. These longer transcripts are processed to yield piRNAs of 26-30 nucleotides independently of DICER, the enzyme responsible for microRNAs (miRNAs) and small interfering RNAs (siRNAs) (reviewed in Girard and Hannon 2008, Siomi et al. 2011, Ishizu et al. 2012, Pillai and Chuma 2012, Bortvin 2013, Chuma and Nakano 2013, Sato and Siomi 2013). The initial step in processing long transcripts to piRNAs is cleavage by PLD6 (MitoPLD), which generates the mature 5' end. The cleavage products of PLD6 are bound by either PIWIL1 (HIWI, MIWI) or PIWIL2 (HILI, MILI) in complexes with several other proteins. The 3' end is trimmed by an unknown exonuclease to generate the mature piRNA. PIWIL1:piRNA complexes appear to be involved in post-transcriptional silencing in the cytosol while PIWIL2:piRNA complexes generate further piRNAs from transposon transcripts and other transcripts in the cytosol. Cleavage products from PIWIL2:piRNA may be loaded into either PIWIL2 or PIWIL4 (HIWI2, MIWI2). Loading into PIWIL2 forms a step in a cytosolic amplification loop called the "ping-pong cycle" which yields further PIWIL2:piRNA complexes from cleaved precursor RNAs. Loading into PIWIL4 yields a complex also containing TDRD9 that translocates to the nucleus and directs DNA methylation of cognate loci, causing transcriptional silencing during spermatogenesis. Transcriptional silencing by piRNAs is necessary to limit transposition of endogenous transposons such as L1 elements in the genome.
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