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Full-Text Articles in Life Sciences

Collaborative Roles For C-Jun N-Terminal Kinase, C-Jun, Serum Response Factor, And Sp1 In Calcium-Regulated Myocardial Gene Expression, Patrick M. Mcdonough, Deanna S. Hanford, Amy B. Sprenkle, Noel R. Mellon, Christopher C. Glembotski Sep 1997

Collaborative Roles For C-Jun N-Terminal Kinase, C-Jun, Serum Response Factor, And Sp1 In Calcium-Regulated Myocardial Gene Expression, Patrick M. Mcdonough, Deanna S. Hanford, Amy B. Sprenkle, Noel R. Mellon, Christopher C. Glembotski

Amy Sprenkle

Electrical stimulation of contractions (pacing) of primary neonatal rat ventricular myocytes increases intracellular calcium and activates a hypertrophic growth program that includes expression of the cardiac-specific gene, atrial natriuretic factor (ANF). To investigate the mechanism whereby pacing increases ANF, pacing was tested for its ability to regulate mitogen-activated protein kinase family members, ANF promoter activity, and the trans-activation domain of the transcription factor, Sp1. Pacing and the calcium channel agonist BAYK 8644 activated c-Jun N-terminal kinase (JNK) but not extracellular signal-regulated kinase. Pacing stimulated ANF-promoter activity approximately 10-fold. Furthermore, transfection with an expression vector for c-Jun, a substrate for JNK, …


Ms2 Coat Protein Mutants Which Bind Qβ Rna, Marc Spingola, David S. Peabody Jul 1997

Ms2 Coat Protein Mutants Which Bind Qβ Rna, Marc Spingola, David S. Peabody

Marc Spingola

The coat proteins of the RNA phages MS2 and Qβ are structurally homologous, yet they specifically bind different RNA structures. In an effort to identify the basis of RNA binding specificity we sought to isolate mutants that convert MS2 coat protein to the RNA binding specificity of Qβ. A library of mutations was created which selectively substitutes amino acids within the RNA binding site. Genetic selection for the ability to repress translation from the Qβ translational operator led to the isolation of several MS2 mutants that acquired binding activity for Qβ RNA. Some of these also had reduced abilities to …


Ac-Mode Atomic Force Microscope Imaging In Air And Solutions With A Thermally Driven Bimetallic Cantilever Probe, Andrew C. Hillier, Allen J. Bard Apr 1997

Ac-Mode Atomic Force Microscope Imaging In Air And Solutions With A Thermally Driven Bimetallic Cantilever Probe, Andrew C. Hillier, Allen J. Bard

Andrew C. Hillier

An ac imaging mode for atomic force microscopy ~AFM! has been developed that employs a thermally driven bimetallic cantilever to sense surface topography. Oscillations are induced in a composite cantilever, comprising a Si3N4 layer and Au overcoat, by local heating with a resistive wire heater placed in close proximity to the cantilever. Cantilever bending occurs upon heating due to the difference in thermal expansion coefficients of the Si3N4 and Au layers. The magnitude of this bending is a function of the heat input, the cantilever geometry, the frequency of the excitation, and the thermal properties of the surrounding medium. A …


Rna Base-Amino Acid Interaction Strengths Derived From Structures And Sequences, Brooke Lustig, S Arora, R L. Jernigan Jan 1997

Rna Base-Amino Acid Interaction Strengths Derived From Structures And Sequences, Brooke Lustig, S Arora, R L. Jernigan

Brooke S. Lustig

We investigate RNA base-amino acid interactions by counting their contacts in structures and their implicit contacts in various functional sequences where the structures can be assumed to be preserved. These frequencies are cast into equations to extract relative interaction energetics. Previously we used this approach in considering the major groove interactions of DNA, and here we apply it to the more diverse interactions observed in RNA. Structures considered are the three different tRNA synthetase complexes, the U1A spliceosomal protein with an RNA hairpin and the BIV TARTat complex. We use binding data for the base frequencies for the seryl, aspartyl …


Complexes Between Nascent Polypeptides And Their Molecular Chaperones In The Cytosol Of Mammalian Cells, Daryl K. Eggers, W. J. Welch, W. J. Hansen Jan 1997

Complexes Between Nascent Polypeptides And Their Molecular Chaperones In The Cytosol Of Mammalian Cells, Daryl K. Eggers, W. J. Welch, W. J. Hansen

Daryl K. Eggers

Folding of newly synthesized proteins in vivo is believed to be facilitated by the cooperative interaction of a defined group of proteins known as molecular chaperones. We investigated the direct interaction of chaperones with nascent polypeptides in the cytosol of mammalian cells by multiple methods. A new approach using a polyclonal antibody to puromycin allowed us to tag and capture a population of truncated nascent polypeptides with no bias as to the identity of the bound chaperones. In addition, antibodies that recognize the cytosolic chaperones hsp70, CCT (TRiC), hsp40, p48 (Hip), and hsp90 were compared on the basis of their …


Direct Measurement Of Diffuse Double-Layer Forces At The Semiconductor/Electrolyte Interface Using An Atomic Force Microscope, Kai Hu, Fu-Ren F. Fan, Allen J. Bard, Andrew C. Hillier Dec 1996

Direct Measurement Of Diffuse Double-Layer Forces At The Semiconductor/Electrolyte Interface Using An Atomic Force Microscope, Kai Hu, Fu-Ren F. Fan, Allen J. Bard, Andrew C. Hillier

Andrew C. Hillier

The forces between a silica probe and an n-type TiO2 single-crystal electrode were measured using an atomic force microscope in an aqueous electrolyte solution. These interactions were a strong function of the solution pH, the presence of specifically adsorbed anions, and the TiO2 electrode potential. For a series of pH values, a strong electrostatic repulsion was seen at high pH and decreased as the pH was reduced. At pH values below 5.5, the interaction became attractive. A series of force measurements between SiO2 and n-type TiO2 showed a repulsive interaction when TiO2 was held at negative electrode potentials, which transformed …