7K3J

Crystal structure of dLC8 in complex with Panoramix TQT+TQ peptide

Summary for 7K3J

• Entry DOI: 10.2210/pdb7k3j/pdb
• Descriptor: Dynein light chain 1, cytoplasmic, Protein panoramix, SULFATE ION (3 entities in total)
• Functional Keywords: piwi, transposon silencing, heterochromatin formation, pirna pathway, transcriptional silencing, rna binding protein, motor protein
• Biological source: Drosophila melanogaster (Fruit fly); More
• Total number of polymer chains: 10
• Total formula weight: 74794.60

Authors

Wang, J.,Patel, D.J. (deposition date: 2020-09-11, release date: 2021-03-03, Last modification date: 2023-10-18)

Primary citation

Schnabl, J.,Wang, J.,Hohmann, U.,Gehre, M.,Batki, J.,Andreev, V.I.,Purkhauser, K.,Fasching, N.,Duchek, P.,Novatchkova, M.,Mechtler, K.,Plaschka, C.,Patel, D.J.,Brennecke, J.
Molecular principles of Piwi-mediated cotranscriptional silencing through the dimeric SFiNX complex.
Genes Dev., 35:392-409, 2021

PubMed Abstract: Nuclear Argonaute proteins, guided by their bound small RNAs to nascent target transcripts, mediate cotranscriptional silencing of transposons and repetitive genomic loci through heterochromatin formation. The molecular mechanisms involved in this process are incompletely understood. Here, we show that the SFiNX complex, a silencing mediator downstream from nuclear Piwi-piRNA complexes in , facilitates cotranscriptional silencing as a homodimer. The dynein light chain protein Cut up/LC8 mediates SFiNX dimerization, and its function can be bypassed by a heterologous dimerization domain, arguing for a constitutive SFiNX dimer. Dimeric, but not monomeric SFiNX, is capable of forming molecular condensates in a nucleic acid-stimulated manner. Mutations that prevent SFiNX dimerization result in loss of condensate formation in vitro and the inability of Piwi to initiate heterochromatin formation and silence transposons in vivo. We propose that multivalent SFiNX-nucleic acid interactions are critical for heterochromatin establishment at piRNA target loci in a cotranscriptional manner.

PubMed: 33574069
DOI: 10.1101/gad.347989.120

Experimental method

X-RAY DIFFRACTION (2.5 Å)