Transcriptional regulation of the GFAP gene is intimately connected with astrocyte function: its initial activation marks the differentiation of astrocytes, and its up‐regulation accompanies the ...reactive response to CNS injury. Studies of GFAP transcription should thus provide insights into multiple regulatory pathways operating in these cells. In addition, they should identify DNA elements that could be used to direct synthesis of other proteins to astrocytes in transgenic animals, permitting creation of disease models, and the testing of cause and effect relationships. This review describes several GFAP cDNA and genomic clones that have been isolated, including homology comparisons of the encoded RNAs and proteins. Cell transfection studies by several laboratories are summarized that have identified a DNA segment immediately upstream of the RNA start site that is essential for transcriptional activity, but which have yielded conflicting results concerning the importance of other segments located both further upstream and downstream of the RNA start site. Two procedures are recounted that have led to the successful expression of GFAP‐transgenes in astrocytes in mice. One of these incorporates the transgene into the first exon of a fragment spanning the entire GFAP gene, while the other links it to a 2 kb 5′‐flanking segment. Results already produced by GFAP‐transgenic studies include demonstration of a neurotoxic effect of the HIV‐1 gp120 coat protein, and creation of a hydrocephalic mouse model.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Quality control mechanisms prevent the cell surface expression of incompletely assembled multisubunit receptors such as the T cell receptor (TCR). The molecular chaperone function of calnexin (IP90, ...p88), a 90-kilodalton protein that resides in the endoplasmic reticulum (ER), in the retention of representative chains of the TCR-CD3 complex in the ER was tested. Truncation mutants of calnexin, when transiently expressed in COS cells, were exported from the ER and either accumulated in the Golgi or progressed to the cell surface. CD3 ε chains cotransfected with the forms of calnexin that were not retained in the ER exited the ER and colocalized with calnexin. Since engineered calnexin determined the intracellular localization of the proteins associated with it, it is concluded that calnexin interacts with incompletely assembled TCR components and retains them in the ER.
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Objective： To assess whether adherence to amiodarone monitoring differed pre- and post-amiodarone restriction template and implementation of the pharmacist-managed clinic. Design： This was a ...retrospective chart review study. Setting： A large, academically-affiliated Veteran Affairs Healthcare System providing primary and tertiary care. Patients： 580 patients were identified as having an active prescription for amiodarone for at least 60 days from January l, 2009 to August 31, 2013 and receiving primary care at the VAAHS （Veterans Affairs Ann Arbor Healthcare System）. Results： Nearly all patients had TSH and LFTs at baseline regardless of study group. Significant associations between baseline rates for CXR, ECG, PFT, and opbthalmologic exams were found, with higher rates in the clinic and template arms compared to usual care. Similar patterns for all monitoring outcome rates were also found for both the 6- and 12-month measures. Conclusions： Patients on amiodarone who are followed by a pharmacist-managed clinic or where a restricted ordering template was used had increased compliance with amiodarone monitoring guidelines compared to usual care. Use of a restricted template may be a reasonable option in place of a pharmacist-managed service.
Protein synthesis (PS) has been considered essential to sustain mammalian life, yet was found to be virtually arrested for weeks in brain and other organs of the hibernating ground squirrel, ...Spermophilus tridecemlineatus. PS, in vivo, was below the limit of autoradiographic detection in brain sections and, in brain extracts, was determined to be 0.04% of the average rate from active squirrels. Further, it was reduced 3-fold in cell-free extracts from hibernating brain at 37 degrees C, eliminating hypothermia as the only cause for protein synthesis inhibition (active, 0.47 ± 0.08 pmol/mg protein per min; hibernator, 0.16 ± 0.05 pmol/mg protein per min, P < 0.001). PS supression involved blocks of initiation and elongation, and its onset coincided with the early transition phase into hibernation. An increased monosome peak with moderate ribosomal disaggregation in polysome profiles and the greatly increased phosphorylation of eIF2α are both consistent with an initiation block in hibernators. The elongation block was demonstrated by a 3-fold increase in ribosomal mean transit times in cell-free extracts from hibernators (active, 2.4 ± 0.7 min; hibernator, 7.1 ± 1.4 min, P < 0.001). No abnormalities of ribosomal function or mRNA levels were detected. These findings implicate suppression of PS as a component of the regulated shutdown of cellular function that permits hibernating ground squirrels to tolerate ``trickle'' blood flow and reduced substrate and oxygen availability. Further study of the factors that control these phenomena may lead to identification of the molecular mechanisms that regulate this state.
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