title: Dry and wet approaches for genome-wide functional annotation of conventional and unconventional transcriptional activators.
abstract: Transcription factors (TFs) are master gene products that regulate gene expression in response to a variety of stimuli. They interact with DNA in a sequence-specific manner using a variety of DNA-binding domain (DBD) modules. This allows to properly position their second domain, called "effector domain", to directly or indirectly recruit positively or negatively acting co-regulators including chromatin modifiers, thus modulating preinitiation complex formation as well as transcription elongation. At variance with the DBDs, which are comprised of well-defined and easily recognizable DNA binding motifs, effector domains are usually much less conserved and thus considerably more difficult to predict. Also not so easy to identify are the DNA-binding sites of TFs, especially on a genome-wide basis and in the case of overlapping binding regions. Another emerging issue, with many potential regulatory implications, is that of so-called "moonlighting" transcription factors, i.e., proteins with an annotated function unrelated to transcription and lacking any recognizable DBD or effector domain, that play a role in gene regulation as their second job. Starting from bioinformatic and experimental high-throughput tools for an unbiased, genome-wide identification and functional characterization of TFs (especially transcriptional activators), we describe both established (and usually well affordable) as well as newly developed platforms for DNA-binding site identification. Selected combinations of these search tools, some of which rely on next-generation sequencing approaches, allow delineating the entire repertoire of TFs and unconventional regulators encoded by the any sequenced genome.
authors.affiliation: Biochemistry and Molecular Biology Unit, Laboratory of Functional Genomics and Protein Engineering, Department of Life Sciences, University of Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Levati
authors.affiliation: Biochemistry and Molecular Biology Unit, Laboratory of Functional Genomics and Protein Engineering, Department of Life Sciences, University of Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Sartini
authors.affiliation: Biochemistry and Molecular Biology Unit, Laboratory of Functional Genomics and Protein Engineering, Department of Life Sciences, University of Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Ottonello
authors.affiliation: Biochemistry and Molecular Biology Unit, Laboratory of Functional Genomics and Protein Engineering, Department of Life Sciences, University of Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Montanini
keywords: HT-SELEX; Moonlighting transcriptional activators; Protein binding microarrays; Transcription factors; Transcriptional activator trap; Yeast/bacterial one-hybrid