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Piggott, C. A.

Publications and source records attributed to Piggott, C. A..

2 recordsLinked to original sources

Methods and techniques enabling multi-kilobase long-range genomic rewrite/replace editing

CRISPR enabled cell and gene therapies have the potential to revolutionize the field of genetic medicine. However, the vast majority of rare diseases remain untreatable due to the limitations of current tools and techniques. To date, most corrective therapeutic approaches have been restricted to mutation-by-mutation approaches, where either HDR, or newer techniques such as base or prime editing, rewrite small regions of DNA at a time ([~]1-100 bp). While these approaches are powerful, short editing windows (relative to the size of human genes) are financially and/or technically incompatible with most rare-disease mutation profiles. Here, we demonstrate for the first time that CRISPR/Cas9 can be used to "rewrite" 7kb+ sections of the human genome simultaneously via a selection-free process we have named "long-range rewriting". Long-range rewriting approaches are compatible with multiple nucleases, cell types and genomic loci, and can be used with both double-strand break (DSB) and non-DSB based approaches.

genetics↗

Caenorhabditis elegans junctophilin has tissue-specific functions and regulates neurotransmission with extended-synaptotagmin

The junctophilin family of proteins tether together plasma membrane (PM) and endoplasmic reticulum (ER) membranes, and couple PM- and ER-localized calcium channels. Understanding in vivo functions of junctophilins is of great interest for dissecting the physiological roles of ER-PM contact sites. Here, we show that the sole C. elegans junctophilin JPH-1 localizes to discrete membrane contact sites in neurons and muscles and has important tissue-specific functions. jph-1 null mutants display slow growth and development due to weaker contraction of pharyngeal muscles, leading to reduced feeding. In the body wall muscle, JPH-1 co-localizes with the PM-localized EGL-19 voltage-gated calcium channel and ER-localized UNC-68/RyR calcium channel, and is required for animal movement. We also find an unexpected cell non-autonomous effect of jph-1 in axon regrowth after injury. In neurons, JPH-1 co-localizes with the membrane contact site protein Extended-SYnaptoTagmin 2 (ESYT-2) and modulates neurotransmission. Interestingly, jph-1 and esyt-2 null mutants display mutual suppression in their response to aldicarb, suggesting that JPH-1 and ESYT-1 have antagonistic roles in neuromuscular synaptic transmission. Our genetic double mutant analysis also reveals that jph-1 functions in overlapping pathways with two PM-localized voltage-gated calcium channels, egl-19 and unc-2, and unc-68/RyR for animal health and development. Finally, we show that unc-68/RyR is required for JPH-1 localization to ER-PM puncta. Our data demonstrate important roles for junctophilin in cellular physiology, and also provide insights into how junctophilin functions together with other calcium channels in vivo.

genetics↗