Global transcriptional regulatory network for Escherichia coli robustly connects gene expression to transcription factor activities

Xin Fang, Anand Sastry, Nathan Mih, Donghyuk Kim, Justin Tan, James T. Yurkovich, Colton J. Lloyd, Ye Gao, Laurence Yang, Bernhard O. Palsson

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Transcriptional regulatory networks (TRNs) have been studied intensely for >25 y. Yet, even for the Escherichia coli TRN-probably the best characterized TRN-several questions remain. Here, we address three questions: (i) How complete is our knowledge of the E. coli TRN; (ii) how well can we predict gene expression using this TRN; and (iii) how robust is our understanding of the TRN? First, we reconstructed a high-confidence TRN (hiTRN) consisting of 147 transcription factors (TFs) regulating 1,538 transcription units (TUs) encoding 1,764 genes. The 3,797 high-confidence regulatory interactions were collected from published, validated chromatin immunoprecipitation (ChIP) data and RegulonDB. For 21 different TF knockouts, up to 63% of the differentially expressed genes in the hiTRN were traced to the knocked-out TF through regulatory cascades. Second, we trained supervised machine learning algorithms to predict the expression of 1,364 TUs given TF activities using 441 samples. The algorithms accurately predicted condition-specific expression for 86% (1,174 of 1,364) of the TUs, while 193 TUs (14%) were predicted better than random TRNs. Third, we identified 10 regulatory modules whose definitions were robust against changes to the TRN or expression compendium. Using surrogate variable analysis, we also identified three unmodeled factors that systematically influenced gene expression. Our computational workflow comprehensively characterizes the predictive capabilities and systems-level functions of an organism's TRN from disparate data types.
Original languageEnglish
JournalProceedings of the National Academy of Sciences of the United States of America
Volume114
Issue number38
Pages (from-to)10286-10291
ISSN0027-8424
DOIs
Publication statusPublished - 2017

Keywords

  • Transcriptional regulation
  • Transcriptomics
  • Matrix factorization
  • Regression

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