| Transcriptional Regulation in Eukaryotes
Naoko Tanese Ph.D.
Associate Professor
Department of Microbiology |
| |
| Research Summary |
The main focus of research in our laboratory is to investigate the mechanisms of transcriptional regulation in mammalian cells. Specifically, we study the role of the transcription factor TFIID in mediating RNA polymerase II-dependent transcriptional activation by a variety of activators in human cells. We are also interested in characterizing the properties of the chromatin remodeling complexes that play fundamental roles in transcriptional initiation. Past research in the lab has focused on elucidating the role of human TAFII130, an integral subunit of the TFIID complex, in transcriptional regulation. We have characterized the molecular interactions between hTAFII130 and selective activators and defined functional consequences of these interactions with respect to transcriptional regulation. We have defined specific regions of hTAFII130 involved in TAFII-TAFII and TAFII-activator interactions. We have reconstituted partial TFIID complexes using the vaccinia virus-based protein expression system and examined the role of individual TAFIIs in transcription and TATA box binding.
I. Proteins that interact with hTAFII130.
Although we have gained much understanding of hTAFII130 function by studying its interactions with known site-specific activators such as Sp1 or CREB, we have yet to identify additional target proteins of hTAFII130 including the conserved central domain. Toward this end, we have carried out a yeast two-hybrid screen to identify proteins that interact with the evolutionarily conserved central domain of hTAFII130. Four amphipathic a helices comprise this domain, which is also present in ETO/MTG8, the transcription factor associated with the t(8;21) chromosomal translocation in an acute myelogenous leukemia. Although the function of the conserved domain remains to be elucidated, it is likely to associate with novel proteins involved in transcriptional regulation.
II. Genes regulated by hTAFII130.
Studies using yeast strains with conditional mutations in specific TAFIIs have uncovered a partial list of genes whose expression is dependent on the selected TAFII. These studies suggest that TAFIIs impart gene-specific control instead of having a global role in transcription. Since hTAFII130 may be unique to metazoans, we wish to identify genes regulated by hTAFII130 in mammalian cells to elucidate the mechanisms of hTAFII130 function. Toward this end, we have carried out oligonucleotide-based microarray analysis to identify genes whose expression is sensitive to levels of hTAFII130 protein. Work is under way to characterize the candidate target genes of hTAFII130.
III. Characterization of the largest subunits of the mammalian SWI/SNF complex.
We have purified the Brahma chromatin remodeling complex to homogeneity from Drosophila and demonstrated that Osa, a protein previously shown to be required for photoreceptor differentiation and embryonic segmentation, is an integral component of the Drosophila SWI/SNF complex (in collaboration with Jessica Treisman, NYU School of Medicine). We are currently investigating the properties of the human homologues of Osa and their potential role in mediating transcriptional activation and repression. |
| |
| Related Images |
Image 1 | Transcriptional activators counter chromatin-mediated repression by recruiting chromatin-remodeling enzymes. In eukaryotic cells, DNA is packaged into a regular array of nucleosomes. Nucleosomes prevent RNA polymerase from accessing the transcriptional intiation site of the gene. Many activators are able to bind to their DNA target sites even in the context of chromatin and through protein-protein interactions, recruit coactivator complexes that alter ('remodel') the local nucleosomes allowing general transcription factors and RNA polymerase to assembly on the core promoter. Remodeling complexes fall into two broad classes: ATP-dependent remodeling enzymes and acetyltransferases. | | |
| Research Information |
Research Interests | Transcriptional Regulation in Mammalian Cells
| Research Keywords | co-activators, gene regulation, TFIID complex, transcription factor, chromatin
| | |
| Research Links |
| Tanese Lab Website |
