HtsRC-Mediated Accumulation of F-Actin Regulates Ring Canal Size During Drosophila melanogaster Oogenesis

Genetics. 2020 Nov;216(3):717-734. doi: 10.1534/genetics.120.303629. Epub 2020 Sep 3.


Ring canals in the female germline of Drosophila melanogaster are supported by a robust filamentous actin (F-actin) cytoskeleton, setting them apart from ring canals in other species and tissues. Previous work has identified components required for the expansion of the ring canal actin cytoskeleton, but has not identified the proteins responsible for F-actin recruitment or accumulation. Using a combination of CRISPR-Cas9 mediated mutagenesis and UAS-Gal4 overexpression, we show that HtsRC-a component specific to female germline ring canals-is both necessary and sufficient to drive F-actin accumulation. Absence of HtsRC in the germline resulted in ring canals lacking inner rim F-actin, while overexpression of HtsRC led to larger ring canals. HtsRC functions in combination with Filamin to recruit F-actin to ectopic actin structures in somatic follicle cells. Finally, we present findings that indicate that HtsRC expression and robust female germline ring canal expansion are important for high fecundity in fruit flies but dispensable for their fertility-a result that is consistent with our understanding of HtsRC as a newly evolved gene specific to female germline ring canals.

Keywords: Drosophila oogenesis; actin cytoskeleton; hu li tai shao; intrinsically disordered protein; ring canal.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / metabolism*
  • Actins / metabolism
  • Animals
  • Calmodulin-Binding Proteins / chemistry
  • Calmodulin-Binding Proteins / genetics
  • Calmodulin-Binding Proteins / metabolism*
  • Cytokinesis*
  • Drosophila Proteins / chemistry
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Drosophila melanogaster
  • Female
  • Filamins / metabolism
  • Oogenesis*
  • Ovum / cytology
  • Ovum / metabolism


  • Actins
  • Calmodulin-Binding Proteins
  • Drosophila Proteins
  • Filamins
  • hts protein, Drosophila