Single-molecule analysis of transcription activation: dynamics of SAGA coactivator recruitment.

Transcription activators are said to stimulate gene expression by 'recruiting' coactivators, yet this vague term fits multiple kinetic models. To directly analyze the dynamics of activator-coactivator interactions, single-molecule microscopy was used to image promoter DNA, a transcription activator and the Spt-Ada-Gcn5 acetyltransferase (SAGA) complex within yeast nuclear extract. SAGA readily but transiently binds nucleosome-free DNA without an activator, while chromatin association occurs primarily when an activator is present.

Histone H3K18 & H3K23 acetylation directs establishment of MLL-mediated H3K4 methylation.

In an unmodified state, positively charged histone N-terminal tails engage nucleosomal DNA in a manner which restricts access to not only the underlying DNA but also key tail residues subject to binding and/or modification. Charge-neutralizing modifications, such as histone acetylation, serve to disrupt this DNA-tail interaction, facilitating access to such residues. We previously showed that a polyacetylation-mediated chromatin "switch" governs the read-write capability of H3K4me3 by the MLL1 methyltransferase complex.

H3K18 & H3K23 acetylation directs establishment of MLL-mediated H3K4 methylation.

In an unmodified state, positively charged histone N-terminal tails engage nucleosomal DNA in a manner which restricts access to not only the underlying DNA, but also key tail residues subject to binding and/or modification. Charge-neutralizing modifications, such as histone acetylation, serve to disrupt this DNA-tail interaction, facilitating access to such residues. We previously showed that a polyacetylation-mediated chromatin "switch" governs the read-write capability of H3K4me3 by the MLL1 methyltransferase complex.

Single-molecule analysis of transcription activation: dynamics of SAGA co-activator recruitment.

Transcription activators are said to stimulate gene expression by "recruiting" coactivators to promoters, yet this term fits several different kinetic models. To directly analyze dynamics of activator-coactivator interactions, single-molecule microscopy was used to image promoter DNA, a transcription activator, and the Spt-Ada-Gcn5 Acetyltransferase (SAGA) complex within nuclear extract. SAGA readily, but transiently, binds nucleosome-free DNA without activator, while chromatin template association occurs nearly exclusively when activator is present.

Cyclic AMP signaling in Dictyostelium promotes the translocation of the copine family of calcium-binding proteins to the plasma membrane.

Background: Copines are calcium-dependent phospholipid-binding proteins found in many eukaryotic organisms and are thought to be involved in signaling pathways that regulate a wide variety of cellular processes. Copines are characterized by having two C2 domains at the N-terminus accompanied by an A domain at the C-terminus. Six copine genes have been identified in the Dictyostelium genome, cpnA - cpnF.

Risk factors for closed-head injuries during military airborne operations.

Introduction: One of the more serious adverse outcomes of military airborne operations is closed-head injuries. This investigation examined risk factors for closed-head injuries in an Army airborne infantry unit.

Methods: Closed-head injuries were defined as energy exchanges in which the head contacted the ground or an object and the soldier sought medical care for external trauma, headache, loss of consciousness, or altered mental state.

Activities associated with injuries in initial entry training.

Previous studies have not reported activities associated with injuries in initial entry training (IET) because these data were seldom available in medical records and not contained in electronic databases. This investigation obtained activities associated with outpatient encounters in IET recorded by primary medical care providers at Fort Leonard Wood, Missouri. Data were entered into a standard database that included fields for diagnosis and activity associated with the injury.

A prospective investigation of injury incidence and risk factors among army recruits in combat engineer training.

Background: United States Army combat engineer (ENG) training is an intense 14-week course designed to introduce new recruits to basic soldiering activities, Army values and lifestyle, and engineering skills and knowledge. The present investigation examined injury rates and injury risk factors in ENG training.

Methods: At the start of their training, 1,633 male ENG recruits were administered a questionnaire containing items on date of birth, height, weight, tobacco use, prior physical activity, and injury history.

A prospective investigation of injury incidence and injury risk factors among Army recruits in military police training.

Background: United States Army military police (MP) training is a 19-week course designed to introduce new recruits to basic soldiering skills, Army values and lifestyle, and law enforcement skills and knowledge. The present investigation examined injury rates and injury risk factors in MP training.

Methods: At the start of training, 1,838 male and 553 female MP recruits were administered a questionnaire containing items on date of birth, height, weight, tobacco use, prior physical activity, injury history, and menstrual history.

Injury rates and injury risk factors among Federal Bureau of Investigation new agent trainees.

Background: A one-year prospective examination of injury rates and injury risk factors was conducted in Federal Bureau of Investigation (FBI) new agent training.

Methods: Injury incidents were obtained from medical records and injury compensation forms. Potential injury risk factors were acquired from a lifestyle questionnaire and existing data at the FBI Academy.

A systematic review of the effects of physical training on load carriage performance.

Soldiers are often required to carry heavy loads during military operations. This article reports on a systematic literature review examining the influence of physical training on load carriage performance. Several literature databases, reference lists, and other sources were explored to find studies that quantitatively examined the effects of physical training on the time taken for individuals to complete a set distance carrying an external load, with the majority of the load contained in a backpack.

The Advanced Tactical Parachute System (T-11): injuries during basic military parachute training.

Background: Since the 1950s, the standard U.S. military troop parachute system has been the T-10.

Military parachuting injuries, associated events, and injury risk factors.

Introduction: The purpose of this investigation was to examine injury incidence, events associated with injury, and injury risk factors during parachuting in an Army airborne infantry unit.

Methods: Injury data were obtained by the investigators on the drop zone and confirmed by a physician. Operational data (potential injury risk factors) were obtained from routine reports published by the infantry unit.