An integrin binding motif in TLN-1/talin plays a minor role in motility and ovulation

Abstract

TLN-1/talin is a conserved focal adhesion protein that forms part of the linkage between the cytoplasmic tail of integrin and the actin cytoskeleton. In C. elegans , TLN-1 is expressed strongly in striated muscle and the gonadal sheath cells. Here, we report that a CRISPR-generated TLN-1 allele TLN-1(W387A), predicted to affect binding of talin to integrins, results in mild phenotypes, including motility defects and ovulation defects. The arrangement of the actin cytoskeleton in the body wall muscles, spermatheca, and sheath appears identical in wild type and TLN-1(W387A) animals. This analysis suggests that W387 in TLN-1 does not have a major effect on the binding of talin to integrin in vivo .

Figure 1. TLN-1(W387A) results in modest motility and oocyte transit defects

A) The tln-1(kq387) strain BU387 thrashed less on average compared to N2 (Student’s t-test; p<0.0002). B) No significant difference in egg laying in M9 solution was observed between BU387 tln-1(kq387) and N2 (Student’s t-test p = 0.7620). C) No significant difference in stimulated egg laying in 3 mg/mL serotonin creatine sulfate monohydrate solution was observed between BU387 tln-1(kq387) and N2 (Student’s t p-value of 0.9828). D-E) Confocal microscopy of the AH3437 TLN-1::GFP(WT) and BU388 TLN-1::GFP(W387A) animals indicating talin expression in body wall muscles (D), spermatheca, and sheath (E), scale bar= 20 mm. F-G) Phalloidin staining indicates actin alignment in spermatheca, sheath, germline, and body wall muscle scale bar= 20 mm. H) Spermathecal occupancy ‘trapping screen’ scoring of TLN-1::GFP(WT) and TLN-1::GFP(W387A) indicates the presence or absence of an embryo in the spermatheca. I-K) Assessment of timing of oocyte transit through the spermatheca (oocyte entry, dwell, and exit time) of of TLN-1::GFP(WT) and TLN-1::GFP(W387A) animals (blue: fertilized oocyte, red: oocyte fragment 'small piece').