Dataset Information

Identifying gene regulatory modules of heat shock response in yeast.

ABSTRACT: A gene regulatory module (GRM) is a set of genes that is regulated by the same set of transcription factors (TFs). By organizing the genome into GRMs, a living cell can coordinate the activities of many genes in response to various internal and external stimuli. Therefore, identifying GRMs is helpful for understanding gene regulation.Integrating transcription factor binding site (TFBS), mutant, ChIP-chip, and heat shock time series gene expression data, we develop a method, called Heat-Inducible Module Identification Algorithm (HIMIA), for reconstructing GRMs of yeast heat shock response. Unlike previous module inference tools which are static statistics-based methods, HIMIA is a dynamic system model-based method that utilizes the dynamic nature of time series gene expression data. HIMIA identifies 29 GRMs, which in total contain 182 heat-inducible genes regulated by 12 heat-responsive TFs. Using various types of published data, we validate the biological relevance of the identified GRMs. Our analysis suggests that different combinations of a fairly small number of heat-responsive TFs regulate a large number of genes involved in heat shock response and that there may exist crosstalk between heat shock response and other cellular processes. Using HIMIA, we identify 68 uncharacterized genes that may be involved in heat shock response and we also identify their plausible heat-responsive regulators. Furthermore, HIMIA is capable of assigning the regulatory roles of the TFs that regulate GRMs and Cst6, Hsf1, Msn2, Msn4, and Yap1 are found to be activators of several GRMs. In addition, HIMIA refines two clusters of genes involved in heat shock response and provides a better understanding of how the complex expression program of heat shock response is regulated. Finally, we show that HIMIA outperforms four current module inference tools (GRAM, MOFA, ReMoDisvovery, and SAMBA), and we conduct two randomization tests to show that the output of HIMIA is statistically meaningful.HIMIA is effective for reconstructing GRMs of yeast heat shock response. Indeed, many of the reconstructed GRMs are in agreement with previous studies. Further, HIMIA predicts several interesting new modules and novel TF combinations. Our study shows that integrating multiple types of data is a powerful approach to studying complex biological systems.

SUBMITTER: Wu WS

PROVIDER: S-EPMC2575218 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Identifying gene regulatory modules of heat shock response in yeast.

Wu Wei-Sheng WS Li Wen-Hsiung WH

BMC genomics 20080923

<h4>Background</h4>A gene regulatory module (GRM) is a set of genes that is regulated by the same set of transcription factors (TFs). By organizing the genome into GRMs, a living cell can coordinate the activities of many genes in response to various internal and external stimuli. Therefore, identifying GRMs is helpful for understanding gene regulation.<h4>Results</h4>Integrating transcription factor binding site (TFBS), mutant, ChIP-chip, and heat shock time series gene expression data, we deve ...[more]

PMID: 18811975

Similar Datasets

Project description:BackgroundThe identification of groups of co-regulated genes and their transcription factors, called transcriptional modules, has been a focus of many studies about biological systems. While methods have been developed to derive numerous modules from genome-wide data, individual links between regulatory proteins and target genes still need experimental verification. In this work, we aim to prioritize regulator-target links within transcriptional modules based on three types of large-scale data sources.ResultsStarting with putative transcriptional modules from ChIP-chip data, we first derive modules in which target genes show both expression and function coherence. The most reliable regulatory links between transcription factors and target genes are established by identifying intersection of target genes in coherent modules for each enriched functional category. Using a combination of genome-wide yeast data in normal growth conditions and two different reference datasets, we show that our method predicts regulatory interactions with significantly higher predictive power than ChIP-chip binding data alone. A comparison with results from other studies highlights that our approach provides a reliable and complementary set of regulatory interactions. Based on our results, we can also identify functionally interacting target genes, for instance, a group of co-regulated proteins related to cell wall synthesis. Furthermore, we report novel conserved binding sites of a glycoprotein-encoding gene, CIS3, regulated by Swi6-Swi4 and Ndd1-Fkh2-Mcm1 complexes.ConclusionWe provide a simple method to prioritize individual TF-gene interactions from large-scale transcriptional modules. In comparison with other published works, we predict a complementary set of regulatory interactions which yields a similar or higher prediction accuracy at the expense of sensitivity. Therefore, our method can serve as an alternative approach to prioritization for further experimental studies.

Project description:The yeast proteins Pkh1 and Pkh2 are functional counterparts of the mammalian 3-phosphoinositide-dependent protein kinase 1 (PDK1). Cells carrying simultaneous deletion in both genes, PKH1 and PKH2 are not viable, at least in some genetic backgrounds (Casamayor et al., 1999; Inagaki et al., 1999). Consequently, a different strategy is needed to study the function of these apparently redundant gene products. The approach that has been successfully used to dissect the functions of these proteins consist in the use of a strain that combine the disruption of PKH2 with the temperature sensitive pkh1D398G allele (Inagaki et al., 1999). Since Pkh1 and Pkh2 phosphorylate Pkc1 in vitro in its activation loop (Thr983), and the cell lysis defects of the pkh1D398G pkh2 strain at the restrictive temperature are partially restored by constitutive activation of the Pkc1-Slt2 MAPK pathway, it has been suggested that the Pkh activity is important for maintenance of the cell wall integrity in S. cerevisiae (Inagaki et al., 1999; Friant et al., 2001). We considered it necessary that a different genetic strategy would be convenient in order to carry out specific studies about the functions of the Pkh proteins. In order to avoid incubations at temperatures that activate the Slt2 pathway, and induce cellular lysis, we decided to use a strategy based on the use of a regulatable promoter. We replaced 487 bp located immediately upstream the start PKH2 codon by a cassette containing the doxycycline-repressed promoter tetO7. This substitution is positioned in a 1.3 kbp intergenic region containing divergent promoters and it seems unlikely that may affect expression of the IZH4, the upstream gene, which encode a family of four paralogous membrane proteins involved in zinc ion homeostasis and whose expression is regulated by fatty acids and zinc altered levels. In this strain (MB002) the PKH2 expression could be switched off by addition of doxycycline. In order to deplete the cell for the Pkh activity, we disrupted both, the PKH1 and PKH3 coding regions, obtaining the new SDP8 strain. Our results show that depletion of Pkh results in a differential transcriptional response in front of a heat shock stress. The general transcriptional response was attenuated in the SDP8 when compared when WT cells, but lack of Pkh activity did not affect the repression of the ribosomal proteins.

Dataset Information

Identifying gene regulatory modules of heat shock response in yeast.

Publications

Identifying gene regulatory modules of heat shock response in yeast.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets