Getting off to a good start.

RNA polymerase II transcription can efficiently occur when mouse embryonic stem cells lack TBP and TBP-like proteins, confirming that this initiation factor may not be as essential as once thought.

Single cell transcriptomics reveal trans-differentiation of pancreatic beta cells following inactivation of the TFIID subunit Taf4.

Regulation of gene expression involves a complex and dynamic dialogue between transcription factors, chromatin remodelling and modification complexes and the basal transcription machinery. To address the function of the Taf4 subunit of general transcription factor TFIID in the regulation of insulin signalling, it was inactivated in adult murine pancreatic beta cells. Taf4 inactivation impacted the expression of critical genes involved in beta-cell function leading to increased glycaemia, lowered plasma insulin levels and defective glucose-stimulated insulin secretion.

Hypomorphic Pathogenic Variants in TAF13 Are Associated with Autosomal-Recessive Intellectual Disability and Microcephaly.

In two independent consanguineous families each with two children affected by mild intellectual disability and microcephaly, we identified two homozygous missense variants (c.119T>A [p.Met40Lys] and c.

TRF2 is recruited to the pre-initiation complex as a testis-specific subunit of TFIIA/ALF to promote haploid cell gene expression.

Mammalian genomes encode two genes related to the TATA-box binding protein (TBP), TBP-related factors 2 and 3 (TRF2 and TRF3). Male Trf2(-/-) mice are sterile and characterized by arrested spermatogenesis at the transition from late haploid spermatids to early elongating spermatids. Despite this characterization, the molecular function of murine Trf2 remains poorly characterized and no direct evidence exists to show that it acts as a bona fide chromatin-bound transcription factor.

Essential role of the TFIID subunit TAF4 in murine embryogenesis and embryonic stem cell differentiation.

TAF4 (TATA-binding protein-associated factor 4) and its paralogue TAF4b are components of the TFIID core module. We inactivated the murine Taf4a gene to address Taf4 function during embryogenesis. Here we show that Taf4a(-/-) embryos survive until E9.

TAF4 inactivation reveals the 3 dimensional growth promoting activities of collagen 6A3.

Collagen 6A3 (Col6a3), a component of extracellular matrix, is often up-regulated in tumours and is believed to play a pro-oncogenic role. However the mechanisms of its tumorigenic activity are poorly understood. We show here that Col6a3 is highly expressed in densely growing mouse embryonic fibroblasts (MEFs).

Trim24-repressed VL30 retrotransposons regulate gene expression by producing noncoding RNA.

Trim24 (Tif1α) and Trim33 (Tif1γ) interact to form a co-repressor complex that suppresses murine hepatocellular carcinoma. Here we show that Trim24 and Trim33 cooperatively repress retinoic acid receptor-dependent activity of VL30-class endogenous retroviruses (ERVs) in liver. In Trim24-knockout hepatocytes, VL30 derepression leads to accumulation of reverse-transcribed VL30 cDNA in the cytoplasm that correlates with activation of the viral-defense interferon responses mimicking the preneoplastic inflammatory state seen in human liver following exogenous viral infection.

Interconversion between active and inactive TATA-binding protein transcription complexes in the mouse genome.

The TATA binding protein (TBP) plays a pivotal role in RNA polymerase II (Pol II) transcription through incorporation into the TFIID and B-TFIID complexes. The role of mammalian B-TFIID composed of TBP and B-TAF1 is poorly understood. Using a complementation system in genetically modified mouse cells where endogenous TBP can be conditionally inactivated and replaced by exogenous mutant TBP coupled to tandem affinity purification and mass spectrometry, we identify two TBP mutations, R188E and K243E, that disrupt the TBP-BTAF1 interaction and B-TFIID complex formation.

Cell-specific occupancy of an extended repertoire of CREM and CREB binding loci in male germ cells.

Background: CREB and CREM are closely related factors that regulate transcription in response to various stress, metabolic and developmental signals. The CREMτ activator isoform is selectively expressed in haploid spermatids and plays an essential role in murine spermiogenesis.

Results: We have used chromatin immunoprecipitation coupled to sequencing (ChIP-seq) to map CREM and CREB target loci in round spermatids from adult mouse testis and spermatogonia derived GC1-spg cells respectively.

Specialization of the general transcriptional machinery in male germ cells.

In adult animals, spermatogenesis involves a continuous differentiation of the spermatogonial stem and progenitor cell population into mature sperm. A unique aspect of this developmental process is the germ cell-specific expression and function of paralogues of components of the general transcription machinery, notably subunits of TFIID. Genetic and biochemical studies show that these paralogues play critical, but mechanistically distinct roles in Drosophila and mouse spermatogenesis.

HMGB4, a novel member of the HMGB family, is preferentially expressed in the mouse testis and localizes to the basal pole of elongating spermatids.

We identified HMGB4, a novel member of the HMGB family lacking the acidic tail typically found in this family. HMGB4 is strongly and preferentially expressed in the adult mouse testis and weakly in the brain, but not in many other tissues. HMGB4 associates with chromatin, and in transfection assays, in contrast to HMGB1, it acts as a potent transcriptional repressor.

Repression of the human dihydrofolate reductase gene by a non-coding interfering transcript.

Alternative promoters within the same gene are a general phenomenon in gene expression. Mechanisms of their selective regulation vary from one gene to another and are still poorly understood. Here we show that in quiescent cells the mechanism of transcriptional repression of the major promoter of the gene encoding dihydrofolate reductase depends on a non-coding transcript initiated from the upstream minor promoter and involves both the direct interaction of the RNA and promoter-specific interference.

Proteolytic cleavage of ALF into alpha- and beta-subunits that form homologous and heterologous complexes with somatic TFIIA and TRF2 in male germ cells.

Male germ cells specifically express paralogues of components of the general transcription apparatus including ALF a paralogue of TFIIAalpha/beta. We show that endogenous ALF is proteolytically cleaved to give alpha- and beta-subunits and we map the proteolytic cleavage site by mass spectrometry. Immunoprecipitations show that ALFalpha- and beta-subunits form a series of homologous and heterologous complexes with somatic TFIIA which is coexpressed in male germ cells.

Polar nuclear localization of H1T2, a histone H1 variant, required for spermatid elongation and DNA condensation during spermiogenesis.

Spermiogenesis entails a major biochemical and morphological restructuring of the germ cell involving replacement of the somatic histones by protamines packing the DNA into the condensed spermatid nucleus and elimination of the cytoplasm during the elongation phase. We describe H1T2, an histone H1 variant selectively and transiently expressed in male haploid germ cells during spermiogenesis. In round and elongating spermatids, H1T2 specifically localizes to a chromatin domain at the apical pole, revealing a polarity in the spermatid nucleus.

Autocatalytic RNA cleavage in the human beta-globin pre-mRNA promotes transcription termination.

New evidence indicates that termination of transcription is an important regulatory step, closely related to transcriptional interference and even transcriptional initiation. However, how this occurs is poorly understood. Recently, in vivo analysis of transcriptional termination for the human beta-globin gene revealed a new phenomenon--co-transcriptional cleavage (CoTC).

Cell-specific nucleolar localization of TBP-related factor 2.

TATA-binding protein (TBP)-related factor 2 (TRF2) is one of four closely related RNA polymerase II transcription factors. We compared the intracellular localizations of TBP and TRF2 during the cell cycle and mitosis in HeLa cells. We show that during interphase, endogenous or exogenously expressed TRF2 is located almost exclusively in the nucleolus in HeLa or Cos cells.

[TBP, a universal transcription factor?].

The TATA binding protein (TBP) is a subunit of several macromolecular complexes required for transcription by the three nuclear RNA polymerases. This observation led to the idea that TBP is a "universal" transcription factor. The discovery of three TBP-related factors and a macromolecular complex which lacks TBP but can support RNA polymerase II transcription in vitro has led to a reappraisal of the universal character of TBP.

RNA polymerase II transcription in murine cells lacking the TATA binding protein.

Inactivation of the murine TATA binding protein (TBP) gene by homologous recombination leads to growth arrest and apoptosis at the embryonic blastocyst stage. However, after loss of TBP, RNA polymerase II (pol II) remains in a transcriptionally active phosphorylation state, and in situ run-on experiments showed high levels of pol II transcription comparable to those of wild-type cells. In contrast, pol I and pol III transcription was arrested.

Distinct functions of TBP and TLF/TRF2 during spermatogenesis: requirement of TLF for heterochromatic chromocenter formation in haploid round spermatids.

TLF (TBP-like factor) is a protein commonly thought to belong to the general transcription initiation complex. TLF is evolutionarily conserved and has been shown to be essential for early development in C. elegans, zebrafish and Xenopus.