@article {2384, title = {Core promoter recognition complex changes accompany liver development.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {108}, year = {2011}, month = {2011 Mar 8}, pages = {3906-11}, abstract = {

Recent studies of several key developmental transitions have brought into question the long held view of the basal transcriptional apparatus as ubiquitous and invariant. In an effort to better understand the role of core promoter recognition and coactivator complex switching in cellular differentiation, we have examined changes in transcription factor IID (TFIID) and cofactor required for Sp1 activation/Mediator during mouse liver development. Here we show that the differentiation of fetal liver progenitors to adult hepatocytes involves a wholesale depletion of canonical cofactor required for Sp1 activation/Mediator and TFIID complexes at both the RNA and protein level, and that this alteration likely involves silencing of transcription factor promoters as well as protein degradation. It will be intriguing for future studies to determine if a novel and as yet unknown core promoter recognition complex takes the place of TFIID in adult hepatocytes and to uncover the mechanisms that down-regulate TFIID during this critical developmental transition.

}, issn = {1091-6490}, doi = {10.1073/pnas.1100640108}, author = {D{\textquoteright}Alessio, Joseph A and Ng, Raymond and Willenbring, Holger and Tjian, Robert} } @article {2388, title = {Shifting players and paradigms in cell-specific transcription.}, journal = {Molecular Cell}, volume = {36}, year = {2009}, month = {2009 Dec 25}, pages = {924-31}, abstract = {

Historically, developmental-stage- and tissue-specific patterns of gene expression were assumed to be determined primarily by DNA regulatory sequences and their associated activators, while the general transcription machinery including core promoter recognition complexes, coactivators, and chromatin modifiers was held to be invariant. New evidence suggests that significant changes in these general transcription factors including TFIID, BAF, and Mediator may facilitate global changes in cell-type-specific transcription.

}, keywords = {Animals, Developmental, Gene Expression Regulation, Genetic, Mediator Complex, Models, Molecular, Promoter Regions, Protein Isoforms, TATA Box Binding Protein-Like Proteins, Tissue Distribution, Transcription, Transcription Factor TFIID}, issn = {1097-4164}, doi = {10.1073/pnas.1100640108}, author = {D{\textquoteright}Alessio, Joseph A and Wright, Kevin J and Tjian, Robert} } @article {2404, title = {IRES-mediated functional coupling of transcription and translation amplifies insulin receptor feedback.}, journal = {Genes \& Development}, volume = {21}, year = {2007}, month = {2007 Jan 15}, pages = {175-83}, abstract = {

It is generally accepted that the growth rate of an organism is modulated by the availability of nutrients. One common mechanism to control cellular growth is through the global down-regulation of cap-dependent translation by eIF4E-binding proteins (4E-BPs). Here, we report evidence for a novel mechanism that allows eukaryotes to coordinate and selectively couple transcription and translation of target genes in response to a nutrient and growth signaling cascade. The Drosophila insulin-like receptor (dINR) pathway incorporates 4E-BP resistant cellular internal ribosome entry site (IRES) containing mRNAs, to functionally couple transcriptional activation with differential translational control in a cell that is otherwise translationally repressed by 4E-BP. Although examples of cellular IRESs have been previously reported, their critical role mediating a key physiological response has not been well documented. Our studies reveal an integrated transcriptional and translational response mechanism specifically dependent on a cellular IRES that coordinates an essential physiological signal responsible for monitoring nutrient and cell growth conditions.

}, keywords = {5{\textquoteright} Untranslated Regions, Animals, Biological, Drosophila melanogaster, Drosophila Proteins, Eukaryotic Initiation Factor-4E, Feedback, Forkhead Transcription Factors, Gene Expression Regulation, Genetic, Insulin, Models, Phosphorylation, Physiological, Protein Biosynthesis, Receptor, Ribosomes, Signal Transduction, Transcription, Transfection}, issn = {0890-9369}, doi = {10.1073/pnas.1100640108}, author = {Marr, Michael T and D{\textquoteright}Alessio, Joseph A and Puig, Oscar and Tjian, Robert} }