Fig. 2: CRISPR screening reveals key role of peptides in the regulation of cell proliferation.

a Schematic map of CRISPR screening process for peptides. b Density map depicting the absolute values of fold changes for sgRNAs targeting essential proteins, scrambled sequences, sORFs, and regions upstream of sORFs.  c, d Jitter (c) and box (d) plots depicting the absolute values of fold changes for sgRNAs targeting essential protein, scramble sequence, sORFs and upstream of sORFs. e Point plot for the screening results of peptides. Red points indicate pro-proliferative peptides, green points indicated anti-proliferative peptides, and gray points indicated non-hit peptides. The criterion was defined as |log₂fold change of sORFs body | > 1 and |log₂fold change of sORFs upstream | < 1. f Statistic of overall detected peptides (8945), peptides designed for CRISPR screening (3094) and phenotypic peptides (1161). g A tally of on-hit peptides with specific genetic or biochemical properties. h Correlation between the absolute values of phenotype score and coding score of peptides analyzed by CPAT. The correlations were characterized by the spearsman correlation coefficient (left). Boxplot for coding potential score comparison of phenotypic and non-phenotypic peptides (right). Wilcoxon test; P < 2.2E−16. i Correlation between the absolute values of phenotype score and peptide amino acid length. The correlations were characterized by the spearsman correlation coefficient (left). Boxplot for peptide amino acid comparison of phenotypic and non-phenotypic peptides (right). Wilcoxon test; P < 2.2E−16. j Correlation between the absolute values of phenotype score and conservation score analyzed by Phastcons. The correlations were characterized by the spearsman correlation coefficient (left). Boxplot for conversation score comparison of phenotypic and non-phenotypic peptides (right). Wilcoxon test; P = 0.0047 E. k Upper: Manhattan map of the peptide genes associated histopathological feature of gastric cancer. Cutoff threshold of significantly changed genes was defined as |log₂fold change | > 1 and adjusted P value < 0.05. Data were presented as individual log₂fold change value. Lower: The number of peptide genes shared by different items. l Venn diagram showing peptides with high coding probability (CPAT > 0.7), domain mapped and association with drug resistance.