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. 2024 Oct 4;27(11):111096. doi: 10.1016/j.isci.2024.111096

Figure 3.

Figure 3

SKIV2L helicase activity is dispensable for the suppression of telomere fragility

(A) Schematic diagram to illustrate the domain organization and features of human SKIV2L. The structurally resolved (via cryo-EM) regions of the SKIV2L subunit extracted from the RNA-bound human SKI complex in the closed state (PDB: 7QDY) is represented by a green colored bar. The SKIV2L subunit harbors the following domains: Ski2 N-terminal (Ski2 N) domain, DEAD/DEAH box helicase (DEAH) domain, ATP binding (ATP) domain, Helicase C-terminal (Helicase C) domain, rRNA-processing arch (rRNA proc-arch) domain and DOB1/SK12/helY-like DEAD box helicases C-terminal (DSHCT) domain. The SKIV2L-V341 residue is highlighted in yellow.

(B) Overview of the structure of the RNA-bound human SKI complex in the closed state, featuring: the helicase SKIV2L, tetratricopeptide repeat protein 37 (TTC37) and WD repeat-containing protein 61 (WDR61).

(C) Telomeric FISH analysis: % of telomere fragility in shCtr and shSKIV2L HEK293 cells expressing GFP or SKIV2L (WT), SKIV2L-K338R, SKIV2L-D423A (means ± SD, n > 20 metaphases, 2 independent experiments). t test ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001, significance is not shown for comparisons with p > 0.06.

(D) Comparison of the structure of the wild-type (WT) SKIV2L DEAD domain and a mutant structure, generated using Missense3D, featuring a valine to glycine 341 mutant. In the WT structure, V341 forms hydrophobic contacts with: A318, L322, V328 and I451. The hydrophobic surface shown is colored according to the Eisenberg hydrophobicity scale.

(E) Telomeric FISH analysis: % of telomere fragility in shCtr and shSKIV2L HEK293 cells expressing GFP or SKIV2L-V341G (means ± SD, n > 20 metaphases, 2 independent experiments). t test ∗∗∗∗p < 0.0001. See also Figure S3.