{'fraction_non_alphanumeric': 0.01155115511551155, 'fraction_numerical': 0.0027502750275027505, 'mean_word_length': 5.427561837455831, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Histone Modifications in Transcriptional Regulation

Chromatin is the collection of proteins that encase chromosomal DNA in eukaryotic cells. The basic unit of chromatin is a nucleosome, a protein complex around which 147 basepairs of DNA are wound. One of the most important questions about chromatin is the influence of chromatin state on gene regulation. Many evidences point towards a significant role for nucleosome positioning in transcriptional control. Beyond nucleosome positioning, patterns of covalent modifications of histone tails are correlated with transcriptionally active and silenced regions, and manifestly play a role in transcriptional regulation and in passing information in an epigenetic manner to offspring. Our goal is to untangle the causal aspect of the correlations between histone state and transcription. To do so, we followed changes in histone state and transcription of yeast genes after a sharp stress stimulation which involves rapid induction and repression of hundreds of genes. We measured the changes in the modification level at different time points following stimulation by using a highresolution tiling microarray with single nucleosome resolution on a thousand nucleosomes. Our findings show that the initial modification changes are affected by Pol2, while Pol2’s initial response is not influenced by changes in the modification level. We also found that the behavior of most of the modifications in response to stress was consistent with the observations made about their behavior in mid-log conditions, i.e. the changes in the modification level associated with gene expression were correlated with the changes in the gene expression. These results leads to another step in understanding the importance of histone modification for the global process of gene regulation.