Acute effect of different doses of caffeinated chewing gum on exercise performance in caffeine-habituated male soccer players.

The ergogenic benefits of caffeine have been well established, but there is scarce research on its chewing gum form. The present research aimed to examine the effects of different doses (100 and 200 mg) of caffeinated chewing gum on muscle strength, vertical jump performance, and ball-kicking speed in trained male soccer players. In a double-blind, randomized counterbalanced, and crossover research design, 14 male soccer players (age = 22 ± 2 y; body mass = 74.

Transcription factor IIS cooperates with the E3 ligase UBR5 to ubiquitinate the CDK9 subunit of the positive transcription elongation factor B.

Elongation of transcription by mammalian RNA polymerase II (RNAPII) is regulated by specific factors, including transcription factor IIS (TFIIS) and positive transcription elongation factor b (P-TEFb). We show that the E3 ubiquitin ligase UBR5 associates with the CDK9 subunit of positive transcription elongation factor b to mediate its polyubiquitination in human cells. TFIIS also binds UBR5 to stimulate CDK9 polyubiquitination.

Genomic location of the human RNA polymerase II general machinery: evidence for a role of TFIIF and Rpb7 at both early and late stages of transcription.

The functions ascribed to the mammalian GTFs (general transcription factors) during the various stages of the RNAPII (RNA polymerase II) transcription reaction are based largely on in vitro studies. To gain insight as to the functions of the GTFs in living cells, we have analysed the genomic location of several human GTF and RNAPII subunits carrying a TAP (tandem-affinity purification) tag. ChIP (chromatin immunoprecipitation) experiments using anti-tag beads (TAP-ChIP) allowed the systematic localization of the tagged factors.

Genotoxic effects of chromium(VI) and cadmium(II) in human blood lymphocytes using the electron microscopy in situ end-labeling (EM-ISEL) assay.

Evaluation of genotoxic effects of potassium chromate (K2CrO4) and cadmium chloride (CdCl2) was carried out in human blood lymphocytes in vitro as measured by the electron microscopy in situ end-labeling (EM-ISEL). EM-ISEL was used to assess DNA single-strand breaks (SSBs) expressed as number of immunogold particles per microm2 of chromatin at both chromosomal and nuclear DNA levels. Human lymphocytes were cultured in supplemented RPMI medium for 72 h including treatment for 2 h with K2CrO4 (0-150 microM), CdCl2 (0-150 microM) or methyl methanesulfonate (500 microM) as a positive control.

RPAP1, a novel human RNA polymerase II-associated protein affinity purified with recombinant wild-type and mutated polymerase subunits.

We have programmed human cells to express physiological levels of recombinant RNA polymerase II (RNAPII) subunits carrying tandem affinity purification (TAP) tags. Double-affinity chromatography allowed for the simple and efficient isolation of a complex containing all 12 RNAPII subunits, the general transcription factors TFIIB and TFIIF, the RNAPII phosphatase Fcp1, and a novel 153-kDa polypeptide of unknown function that we named RNAPII-associated protein 1 (RPAP1). The TAP-tagged RNAPII complex is functionally active both in vitro and in vivo.

Interaction networks of the molecular machines that decode, replicate, and maintain the integrity of the human genome.

The interaction of many proteins with genomic DNA is required for the expression, replication, and maintenance of the integrity of mammalian genomes. These proteins participate in processes as diverse as gene transcription and mRNA processing, as well as in DNA replication, recombination, and repair. This intricate system, where the various nuclear machineries interact with one another and bind to either common or distinct DNA regions to create an impressive network of protein-protein and protein-DNA interactions, is made even more complex by the need for a very stringent control in order to ensure normal cell growth and differentiation.