Project description:We report the PAMs of AsCas12a using a cell-free TXTL-based cleavage assay. By adding randomized PAM library and AsCas12a-gRNA in vitro, functional PAM sequences were cleaved, while non-functional PAMs remained. By amplifying the non-cleaved DNA, we use next-generation sequencing to analyze the depletion of functional PAMs of AsCas12a.
Project description:We report the PAMs of phylogenetically-diverse Cas12a nucleases using a cell-free TXTL-based PAM screen. By adding a 5N randomized PAM library and Cas12a-gRNA in vitro, recognized PAM sequences were cleaved, while non-recognized PAMs remained. By amplifying the non-cleaved DNA, we used next-generation sequencing to analyze the depletion of functional PAMs of these Cas12a nucleases.
Project description:We report the PAMs of NmeCas9 using a cell-free TXTL-based cleavage assay. By adding randomized PAM library and NmeCas9-gRNA in vitro, functional PAM sequences were cleaved, while non-functional PAMs remained. By amplifying the non-cleaved DNA, we use next-generation sequencing to analyze the depletion of functional PAMs of NmeCas9.
Project description:Our findings provide a novel version of AsCas12a variant with low off-target effects, especially capable of dealing with the high off-targeting at the distal region from the PAM.
Project description:There is an absolute requirement of Pax7 for the normal function of MuSCs during regenerative myogenesis in skeletal muscle at any stage of life. Here using RNA-seq, H3K27ac and Pax7 ChIP-seq, we discover PAM-1 (Pax7 Associated Muscle lncRNA) that is enriched in activated skeletal muscle satellite cells (ASCs) 24 and 48 hours after activation. Knockdown of PAM-1 reduces proliferating Pax7+Myod+ ASCs number, while overexpression of PAM-1 increases ASCs number. Mechanistically, PAM-1 is located on ASCs and myoblast specific super-enhancer (SE), and we categorize it as seRNA. Through a series of multiomics analysis of PAM-1 interactome in myoblast including PAM-1-DNA interaction by ChIRP-seq, PAM-1 SE-DNA interaction by 4C-seq, PAM-1-protein interaction by mass spectrometry and ChIP-seq, we identify a novel class of transcriptional regulation that seRNA PAM-1 interacts with RNA binding protein Ddx5 and tethers PAM-1 SE to regulate inter-chromosomal targets Timp2. Altogether, our findings identify PAM-1 is driven by Pax7 in ASC and myoblast to regulate myogenic activation through binding with Ddx5 and targeting Timp2.
Project description:There is an absolute requirement of Pax7 for the normal function of MuSCs during regenerative myogenesis in skeletal muscle at any stage of life. Here using RNA-seq, H3K27ac and Pax7 ChIP-seq, we discover PAM-1 (Pax7 Associated Muscle lncRNA) that is enriched in activated skeletal muscle satellite cells (ASCs) 24 and 48 hours after activation. Knockdown of PAM-1 reduces proliferating Pax7+Myod+ ASCs number, while overexpression of PAM-1 increases ASCs number. Mechanistically, PAM-1 is located on ASCs and myoblast specific super-enhancer (SE), and we categorize it as seRNA. Through a series of multiomics analysis of PAM-1 interactome in myoblast including PAM-1-DNA interaction by ChIRP-seq, PAM-1 SE-DNA interaction by 4C-seq, PAM-1-protein interaction by mass spectrometry and ChIP-seq, we identify a novel class of transcriptional regulation that seRNA PAM-1 interacts with RNA binding protein Ddx5 and tethers PAM-1 SE to regulate inter-chromosomal targets Timp2. Altogether, our findings identify PAM-1 is driven by Pax7 in ASC and myoblast to regulate myogenic activation through binding with Ddx5 and targeting Timp2.
Project description:Plasmids were constructed harboring protospacers that are perfect targets for spacers #4 and #21 of the array, but contain NNN (all possible PAM combinations) immediately upstream of the protospacer. The plasmids were introduced into V. cholerae with or without a functional CRISPR-cas system and cells were plated on selective media. Cells were collected and the protospacer plasmids were sequenced in a high throughput manner. PAMs were counted using a custom python script
Project description:Neurons and endocrine cells package peptides in secretory granules (large dense core vesicles; LDCVs) for storage and stimulated release. Studies of PAM, an essential secretory granule membrane enzyme, revealed a pathway that can relay information from secretory granules to the nucleus, resulting in alterations in gene expression. The cytosolic domain of PAM, a type 1 membrane enzyme essential for the production of amidated peptides, is basally phosphorylated by Uhmk1 and other Ser/Thr kinases. Proopiomelanocortin processing in AtT-20 corticotrope tumor cells was increased when Uhmk1 expression was reduced. Uhmk1 was concentrated in the nucleus, but cycled rapidly between nucleus and cytosol. Endoproteolytic cleavage of PAM releases a soluble cytosolic domain (CD) fragment that localizes to the nucleus. Localization of PAM-CD to the nucleus was decreased when PAM-CD with phosphomimetic mutations was examined and when active Uhmk1 was simultaneously over-expressed. Membrane-tethering Uhmk1 did not eliminate its ability to exclude PAM-CD from the nucleus, suggesting that cytosolic Uhmk1 could cause this response. Microarray analysis demonstrated the ability of PAM to increase expression of a small subset of genes, including aquaporin 1 (Aqp1) in AtT-20 cells. Aqp1 mRNA levels were higher in wildtype mice than in mice heterozygous for PAM, indicating that a similar relationship occurs in vivo. Expression of PAM-CD also increased Aqp1 levels while expression of Uhmk1 diminished Aqp1 expression. The outlines of a pathway that ties secretory granule metabolism to the transcriptome are thus apparent. Three separate clones of AtT-20 mouse corticotrope tumor cells stably transfected with doxycycline-inducible rat PAM-1 (clones 14, 6_1, 6_2) were treated with cotrol or doxycycline medium for 48 hours. Total mRNA was isolated and hybridized to an Illumina MouseWG-6 v 2.0 whole genome BeadChip.