Establishment And Regulation Of Epithelial Enhancers By P63

The transcription factor p63 is a key mediator of epidermal commitment, development, and differentiation. Point mutations in p63 in human patients lead to developmental defects, including orofacial clefting, one of the most common congenital defects in humans. To date, knowledge is limited about how pivotal is p63’s role in human craniofacial development, due in part to a lack of tractable models to study de novo expression of p63 and its role at developmentally regulated genes. Using an inducible trans-differentiation model, combined with epigenomic sequencing and multi-cohort meta-analysis of GWAS data, we show that p63 establishes enhancers at craniofacial development genes to modulate their transcription. We further identify histone methyltransferase KMT2D as a key interacting partner of p63 at these enhancers and identify a novel role for this histone methyltransferase in maintaining epithelial homeostasis. Our results demonstrate that disease-specific substitution mutation in the DNA binding domain or SAM protein interaction domain of p63 respectively eliminate or reduce establishment of these enhancers. Finally, we show enhancers established by p63 are highly enriched for SNPs associated with nonsyndromic cleft lip +/- cleft palate (CL/P). These orthogonal approaches indicate a strong molecular link between p63 enhancer function and CL/P, illuminating molecular mechanisms underlying this developmental defect and revealing vital regulatory elements and new candidate causative genes

New synthetic routes to Triazolo-benzodiazepine analogues:expanding the scope of the bump-and-hole approach for selective Bromo and Extra-Terminal (BET) bromodomain inhibition

We describe new synthetic routes developed toward a range of substituted analogues of bromo and extra-terminal (BET) bromodomain inhibitors I-BET762/JQ1 based on the triazolo-benzodiazepine scaffold. These new routes allow for the derivatization of the methoxyphenyl and chlorophenyl rings, in addition to the diazepine ternary center and the side chain methylene moiety. Substitution at the level of the side chain methylene afforded compounds targeting specifically and potently engineered BET bromodomains designed as part of a bump and hole approach. We further demonstrate that marked selectivity for the second over the first bromodomain can be achieved with an indole derivative that exploits differential interaction with an aspartate/histidine conservative substitution on the BC loop of BET bromodomains

Establishment and Regulation of Epithelial Enhancers by P63

The transcription factor p63 is a key mediator of epidermal commitment, development, and differentiation. Point mutations in p63 in human patients lead to developmental defects, including orofacial clefting, one of the most common congenital defects in humans. To date, knowledge is limited about how pivotal is p63’s role in human craniofacial development, due in part to a lack of tractable models to study de novo expression of p63 and its role at developmentally regulated genes. Using an inducible trans-differentiation model, combined with epigenomic sequencing and multi-cohort meta-analysis of GWAS data, we show that p63 establishes enhancers at craniofacial development genes to modulate their transcription. We further identify histone methyltransferase KMT2D as a key interacting partner of p63 at these enhancers and identify a novel role for this histone methyltransferase in maintaining epithelial homeostasis. Our results demonstrate that disease-specific substitution mutation in the DNA binding domain or SAM protein interaction domain of p63 respectively eliminate or reduce establishment of these enhancers. Finally, we show enhancers established by p63 are highly enriched for SNPs associated with nonsyndromic cleft lip +/- cleft palate (CL/P). These orthogonal approaches indicate a strong molecular link between p63 enhancer function and CL/P, illuminating molecular mechanisms underlying this developmental defect and revealing vital regulatory elements and new candidate causative genes

Decorating chromatin for enhanced genome editing using CRISPR-Cas9

CRISPR-associated (Cas) enzymes have revolutionized biology by enabling RNA-guided genome editing. Homology-directed repair (HDR) in the presence of donor templates is currently the most versatile method to introduce precise edits following CRISPR-Cas-induced double-stranded DNA cuts, but HDR efficiency is generally low relative to end-joining pathways that lead to insertions and deletions (indels). We tested the hypothesis that HDR could be increased using a Cas9 construct fused to PRDM9, a chromatin remodeling factor that deposits histone methylations H3K36me3 and H3K4me3 to mediate homologous recombination in human cells. Our results show that the fusion protein contacts chromatin specifically at the Cas9 cut site in the genome to increase the observed HDR efficiency by threefold and HDR:indel ratio by fivefold compared with that induced by unmodified Cas9. HDR enhancement occurred in multiple cell lines with no increase in off-target genome editing. These findings underscore the importance of chromatin features for the balance between DNA repair mechanisms during CRISPR-Cas genome editing and provide a strategy to increase HDR efficiency

DNA capture by a CRISPR-Cas9-guided adenine base editor.

CRISPR-Cas-guided base editors convert A•T to G•C, or C•G to T•A, in cellular DNA for precision genome editing. To understand the molecular basis for DNA adenosine deamination by adenine base editors (ABEs), we determined a 3.2-angstrom resolution cryo-electron microscopy structure of ABE8e in a substrate-bound state in which the deaminase domain engages DNA exposed within the CRISPR-Cas9 R-loop complex. Kinetic and structural data suggest that ABE8e catalyzes DNA deamination up to ~1100-fold faster than earlier ABEs because of mutations that stabilize DNA substrates in a constrained, transfer RNA-like conformation. Furthermore, ABE8e's accelerated DNA deamination suggests a previously unobserved transient DNA melting that may occur during double-stranded DNA surveillance by CRISPR-Cas9. These results explain ABE8e-mediated base-editing outcomes and inform the future design of base editors

MOESM2 of Comprehensive analysis of histone post-translational modifications in mouse and human male germ cells

Additional file 2. Relative abundance of additional histone PTMs on H3 in human sperm. Dotplot demonstrating relative abundance of individual and combinatorial PTMs on H3 in different individual sperm samples