Project Details
The role of bromodomain proteins for transcription of translationally repressed mRNAs with relevance for spermiogenesis and the identification of direct and indirect target genes of bromodomain proteins.
Applicant
Professorin Dr. Renate Renkawitz-Pohl, since 9/2016
Subject Area
Reproductive Medicine, Urology
Developmental Biology
Developmental Biology
Term
from 2013 to 2019
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 231955137
Cell type specific transcription programs are a major feature of metazoans prerequisite for the specialisation of different cell types during development and tissue maintenance. By a conserved cellular differentiation process, spermatogenesis leads to formation of haploid sperm for successful reproduction. In Drosophila and in mammals, post-meiotic spermatid differentiation depends on several translationally repressed and stored mRNAs that are often expressed exclusively in the testis through a cell-type-specific transcriptional program. In Drosophila, transcription of translationally repressed and stored mRNAs is dependent on testis-specific TATA-box binding protein associated factors (tTAFs). A testis-specific TFIID complex encompassing tTAFs and a testis-enriched isoform of TAF1 (TAF1-2) is postulated to exist that turns on transcription of genes relevant for spermiogenesis. Previously, we proposed the testis-specifically expressed bromodomain protein tBRD-1 to act as cofactor and/or effector of tTAFs to activate transcription of a subset of tTAF target genes. Recently, we performed microarray analyses (wild-type versus tbrd-1 mutants) and could show that tBRD-1 can function in both gene activation as well as repression. Within the project of this application, we will concentrate on the activating function of tBRD-1. Firstly, we plan to validate (by quantitative real-time RT-PCR and histological methods) and bioinformatically analyse tBRD-1 target genes (identified by microarray analyses). In addition, our aim is to discriminate between direct and indirect target genes of tBRD-1. Therefore, we are going to perform chromatin immunoprecipitation (ChIP) followed by sequencing (ChIP-Seq) and compare these data with our microarray data.tBRD-2 and tBRD-3 enable us to characterise two additional, testis-specifically expressed bromodomain proteins that colocalise with tBRD-1 and tTAFs. Yeast-two-hybrid experiments gave evidence that tBRD-1 interacts with the tTAF Sa, tBRD-2 and tBRD-3. We hypothesise that tBRDs might act in a complex together and/or individually to mediate transcription of a certain subset and/or different subsets of translationally repressed and stored mRNAs with relevance for spermiogenesis.A further goal is the generation and analysis of tbrd-2 and tbrd-3 mutants to compare the phenotypes with that of tbrd-1 mutants. Moreover, we will perform ChIP-Seq experiments for tBRD-2 and tBRD-3. This allows us to identify common and/or different target genes of all three bromodomain proteins. Finally, our aim is to validate our yeast-two-hybrid data in vivo by performing coimmuno¬precipitations (CoIPs).
DFG Programme
Research Grants
Participating Institution
Justus-Liebig-Universität Gießen
Fachbereich Biologie und Chemie
Institut für Genetik
Fachbereich Biologie und Chemie
Institut für Genetik
Ehemalige Antragstellerin
Dr. Christina Pütz-Rathke, until 8/2016