Homology Directed Repair (HDR) enables precise genome editing, but the implementation of HDR-based therapies is hindered by limited efficiency in comparison to methods that exploit alternative DNA ...repair routes, such as Non-Homologous End Joining (NHEJ). In this study, we develop a functional, pooled screening platform to identify protein-based reagents that improve HDR in human hematopoietic stem and progenitor cells (HSPCs). We leverage this screening platform to explore sequence diversity at the binding interface of the NHEJ inhibitor i53 and its target, 53BP1, identifying optimized variants that enable new intermolecular bonds and robustly increase HDR. We show that these variants specifically reduce insertion-deletion outcomes without increasing off-target editing, synergize with a DNAPK inhibitor molecule, and can be applied at manufacturing scale to increase the fraction of cells bearing repaired alleles. This screening platform can enable the discovery of future gene editing reagents that improve HDR outcomes.
Species belonging to
Aspergillus
section
Nigri
are widespread in the vineyard environment, both in soil and on plant surfaces. We used plate counts and droplet digital PCR (ddPCR) methods to compare ...populations of the four most prevalent species (
A. carbonarius, A. niger, A. welwitschiae
, and
A. tubingensis
) over two consecutive years in conventional and organic vineyards, to determine whether management affects the potential distribution of mycotoxigenic
Aspergillus
species. In 2016, plate counts showed that soil populations of total filamentous fungi and of
Aspergillus
section
Nigri
species were not significantly different between conventional and organic vineyards. In 2017, while total fungal populations in soil were not significantly different,
Aspergillus
section
Nigri
populations were significantly higher in organic vineyard soil. In both years, there were no significant differences in total fungal populations and in
Aspergillus
section
Nigri
populations on fruit surfaces collected from conventional and organic vineyards. Likewise, ddPCR methods did not show significant differences in percent distribution of
Aspergillus
species in soil and fruit between conventional and organic vineyards. These results suggest that intervention strategies for preharvest control of potential mycotoxigenic fungi are likely to be equally compatible with either vineyard management strategy.
