The 26-amino acid beta-motif of the Pit-1beta transcription factor is a dominant and independent repressor domain.

The POU-homeodomain transcription factor Pit-1 governs the pituitary cell-specific expression of Pit-1, GH, prolactin (PRL), and TSHbeta genes. Alternative splicing generates Pit-1beta, which contains a 26-amino acid beta-domain inserted at amino acid 48, in the middle of the Pit-1 transcription activation domain (TAD). Pit-1beta represses GH, PRL, and TSHbeta promoters in a pituitary-specific manner, because Pit-1beta activates these same promoters in HeLa nonpituitary cells.

Differential utilization of transcription activation subdomains by distinct coactivators regulates Pit-1 basal and Ras responsiveness.

The POU-homeodomain transcription factor Pit-1 governs ontogeny and cell-specific gene expression of pituitary lactotropes, somatotropes, and thyrotropes. The splice isoform, Pit-1beta, inserts a 26-amino acid (AA) repressor at AA48 in the Pit-1 transcription activation domain (TAD). The Pit-1 TAD contains a basal regulatory subregion, R1 (AA1-45), and a basal and Ras-responsive region, R2 (AA46-80).

Novel single-base deletional mutation in major intrinsic protein (MIP) in autosomal dominant cataract.

Purpose: To further elucidate the cataract phenotype, and identify the gene and mutation for autosomal dominant cataract (ADC) in an American family of European descent (ADC2) by sequencing the major intrinsic protein gene (MIP), a candidate based on linkage to chromosome 12q13.

Design: Observational case series and laboratory experimental study.

Methods: We examined two at-risk individuals in ADC2.

Pit-1beta reduces transcription and CREB-binding protein recruitment in a DNA context-dependent manner.

Many transcription factors are expressed as multiple isoforms with distinct effects on the regulation of gene expression, and the functional consequences of structural differences between transcription factor isoforms may allow for precise control of gene expression. The pituitary transcription factor isoforms Pit-1 and Pit-1beta differentially regulate anterior pituitary hormone gene expression. Pit-1 is required for the development of and appropriate hormone expression by anterior pituitary somatotrophs and lactotrophs.

Equilibrium analysis of high affinity interactions using BIACORE.

BIACORE biosensors are useful for measuring reaction kinetics and calculating affinity constants for macromolecular interactions. However, one drawback with the flow system used in these instruments is that the standard injection procedures limit the amount of time available to collect association-phase data. This is especially problematic during equilibrium analysis of high affinity interactions.

Characterization of the cooperative function of inhibitory sequences in Ets-1.

DNA binding by the eukaryotic transcription factor Ets-1 is negatively regulated by an intramolecular mechanism. Quantitative binding assays compared the DNA-binding activities of native Ets-1, three deletion mutants, and three tryptic fragments. Ets-1 and activated Ets-1 polypeptides differed in DNA-binding affinity as much as 23-fold.

The ClpX heat-shock protein of Escherichia coli, the ATP-dependent substrate specificity component of the ClpP-ClpX protease, is a novel molecular chaperone.

All major classes of protein chaperones, including DnaK (the Hsp70 eukaryotic equivalent) and GroEL (the Hsp60 eukaryotic equivalent) have been found in Escherichia coli. Molecular chaperones enhance the yields of correctly folded polypeptides by preventing aggregation and even by disaggregating certain protein aggregates. Previously, we identified the ClpX heat-shock protein of E.

Inducible binding to the c-fos serum response element during T cell activation is regulated by a phosphotyrosine-containing protein.

The proto-oncogene c-fos is an immediate-early gene, and one of the first genes transcribed after stimulation of most cells with a variety of ligands. Fos expression may be a pivotal event in converting ligand-receptor interactions at the membrane into functional modulation of cell phenotype. The serum response element (SRE) in the c-fos regulatory region participates in induction of transcription by various growth factors and by phorbol esters and subsequent squelching of transcription.

Interaction of murine ets-1 with GGA-binding sites establishes the ETS domain as a new DNA-binding motif.

The proto-oncogene ets-1 is the founding member of a new family of eukaryotic transcriptional regulators. Using deletion mutants of murine ets-1 cDNA expressed in Escherichia coli, we show that the DNA-binding domain corresponds closely to the ETS domain, an 85-amino-acid region that is conserved among ets family members. To investigate the specificity of DNA binding of the ETS domain, we mapped the DNA contacts of a monomeric Ets-1 fragment by chemical protection and interference assays.

Development of a somatic cell hybrid mapping panel and molecular probes for human chromosome 3.

A somatic cell hybrid mapping panel and molecular probes have been developed for human chromosome 3. This panel defines 11 regions for the short and long arms of the chromosome. Four hundred thirty-two probes have been mapped using these hybrids.

Nature of the immunogenic moiety recognized by the human T cell proliferating in response to tetanus toxoid antigen.

This study was undertaken to investigate the nature of the immunogenic moiety recognized by the human T cell which proliferates in response to tetanus toxoid (TT) antigen. Immunosorbent-purified anti-TT IgG antibodies failed, even when added in great excess, to inhibit T cell proliferation in response to TT. Urea-denatured (UD) TT antigen containing less than 1% native TT, as assessed by its reactivity with antibodies raised against native TT, triggered proliferation in T cells to an extent equal to that seen with native TT.

Macrophage T cell interaction in man: binding of antigen-specific human proliferating and helper T cells to antigen-pulsed macrophages.

Adsorption of T cells over monolayers of autologous, but not allogeneic, macrophages (M phi) pulsed with tetanus toxoid (TT) antigen resulted in the specific depletion of the capacity of the T cells to proliferate and to release T cell helper factor in response to stimulation, with TT antigen. T cells that bound to the TT-pulsed M phi monolayers were specifically enriched in their capacity to proliferate in response to TT. Turkey antiserum to the human B cell glycoprotein p 29,34, but not turkey antiserum to human beta 2 microglobulin, inhibited the binding of TT-reactive T cells to TT-pulsed M phi.

Macrophage T-cell interaction in man: handling of tetanus toxoid antigen by human monocytes.

An absolute requirement for monocytes was demonstrated in the T-cell proliferative response to tetanus toxoid (TT) antigen. Antigen-pulsed monocytes were shown to be effective in triggering T-cell proliferation. Using 125I-radiolabeled TT antigen, uptake by monocytes increased progressively over an 18-hr period, at which time 80-85% of the monocytes contained radiolabeled material.