Supplementary MaterialsSupplementary Information 42003_2020_836_MOESM1_ESM
January 12, 2021
Supplementary MaterialsSupplementary Information 42003_2020_836_MOESM1_ESM. appearance of checkpoint regulator p21 ((gene activity is normally regulated on the chromatin level isn’t entirely understood. In today’s study, we attempt to investigate the function of NM1 in the transcriptional response to DNA harm. We discovered that NM1 is mixed up in regulation of gene activation directly. Using embryonic fibroblasts from an NM1-knockout (KO) mouse, we demonstrate that lack of NM1 network marketing leads to constitutive DNA harm. Consistent with these observations, NM1 KO mouse embryonic fibroblasts (MEFs) display higher proliferation prices, improved -H2AX foci, and gene manifestation profiles obtained by RNA sequencing (RNA-Seq) corresponding to a p21 mutant phenotype. In addition, chromatin immunoprecipitation sequencing (ChIP-seq) and ChIP quantitative Delavirdine mesylate PCR (qPCR) experiments show that NM1 is enriched at the transcription start site (TSS) of the gene and Delavirdine mesylate occupancy is enhanced upon DNA damage. Delavirdine mesylate In MEFs subjected to NM1 knockdown (KD) by small interfering RNA (siRNA), p21 expression is significantly downregulated and we show that this is directly caused by impaired recruitment of the HAT PCAF and the HMT Set1 with loss of H3 acetylation and methylation. We propose a new role for NM1 in the transcriptional response to DNA damage through a chromatin-based mechanism. Results Epigenetic signatures and global transcription are altered in the absence of NM1 Previous studies have shown that NM1 distribution across the mammalian genome correlates with RNA Polymerase II and active epigenetic marks at TSS of class II promoters2. To test whether NM1 affects the distribution of histone marks, we performed high-content phenotypic profiling of primary MEFs derived from IL8RA NM1 wild-type (WT) and KO embryos (Supplementary Fig.?1a). Cells were stained with antibodies against epigenetic marks for constitutive heterochromatin (H3K9me3), active enhancers (H3K27ac and H3K4me1), and euchromatin (H3K9ac and H3K4me3) (Fig.?1a). Staining was quantified by using the Compartmental Analysis BioApplication software inbuilt in the High Content Screening platform and at least 10,000 cells were used for each measurement (Fig.?1b). Except for the repressive Delavirdine mesylate mark H3K9me3 whose levels increased in NM1 KO cells, we found significant drops in the levels of each of the active epigenetic marks tested in KO cells compared with WT (Fig.?1a, b). Results from western blotting analysis with the same antibodies correlate with the data obtained from high-content phenotypic profiling (Fig.?1c, d and Supplementary Fig.?4). Open in a separate window Fig. 1 Histone epigenetic signatures are altered in the absence of NM1.a NM1 WT and KO cells were immunostained with antibodies against different histone marks specific for heterochromatin (H3K9me3), euchromatin (H3K9ac and H3K4me3), and gene enhancers (H3K27ac and H3K4me1). Representative pictures for each staining are showed. Scale bar is 5?m. b Nuclear staining intensity was quantified by high-content phenotypic profiling. Each box plot represents mean value and first and third quartile values. Error bars represents minimum and maximum values. For each measurement, at least 10,000 nuclei have been measured. *gene upon DNA damage As both NM1 and p53 interact with the HAT PCAF2,5,35,36, we next examined whether they are part of the same complex and synergize under DNA damage conditions to activate the gene. For this, we treated cells with 10?M Etoposide for 2?h, followed by 10?h incubation in full Dulbeccos modified Eagles medium (DMEM). We next prepared lysates and subjected them to co-immunoprecipitations with antibodies against NM1, p53, PCAF, and nonspecific rabbit immunoglobulins (IgG) (Fig.?5a and Supplementary Fig.?4). The results show that upon DNA damage, NM1, p53, and PCAF can be co-precipitated from total lysates, whereas control GAPDH remains in flow-through control and small fraction IgG will not precipitate the protein. In.