Biomedical subjects

I Gander

Publications and source records attributed to I Gander.

8 recordsLinked to original sources

PubMed1992

The beta subunit of the Fc epsilon RI is associated with the Fc gamma RIII on mast cells.

Fc epsilon RI is a tetrameric receptor, composed of a ligand recognition subunit, alpha, a beta chain, and dimeric gamma chains. Previous studies have indicated that the dimeric gamma chain is associated with Fc gamma RIIIA (CD16) on natural killer cells and macrophages as well as the clonotypic T cell receptor. Here we show that in mast cells, in addition to the dimeric gamma chains, the beta subunit is associated not only with Fc epsilon RI, but also with Fc gamma RIIIA. Functional reconstitution studies with a mastocytoma cell line indicate that Fc gamma RIIIA composed of alpha, beta, and gamma subunits has the capacity for signal transduction. These studies suggest that through the association of alternative ligand recognition subunits (alpha epsilon, alpha gamma), a common signal transduction complex (beta gamma 2) mediates similar biochemical and effector functions in response to immunoglobulin G (IgG) and IgE.

Animals↗

PubMed1992

Positive cis-acting regulatory sequences mediate proper control of POL1 transcription in Saccharomyces cerevisiae.

The 5'ACGCGT3' MluI motif, which is found in the upstream region of several yeast DNA-synthesis genes which are periodically expressed during the mitotic cell-cycle, is present twice in the 5' non-coding region of the DNA-polymerase alpha gene (POL1). Deletion of the most distal repeat does not affect POL1 transcription, while the adjacent 40 base-pair (bp) downstream sequence is necessary both for the proper level and the fluctuation of POL1 mRNA. This region contains the 5'ACGCGTCGCGT3' sequence, which is sufficient to control periodic transcription of a CYC1-lacZ reporter gene with the same kinetics observed for POL1. The adjacent 29 bp AT-rich region does not show any activity by itself, but it acts synergistically in conjunction with at least one MluI hexamer to stimulate CYC1-lacZ expression. By further deletion analysis, DNA sequences necessary to initiate POL1 transcription at the proper sites have also been identified.

Base Sequence↗

PubMed1991

A subunit common to an IgG Fc receptor and the T-cell receptor mediates assembly through different interactions.

The zeta subunit is a component of the Fc gamma receptor of natural killer cells (Fc gamma RIII or CD16), as well as the multimeric T-cell receptor/CD3 complex, and is required for assembly of both native receptors. The role of the zeta subunit in human Fc gamma RIIIA assembly differs from its role in T-cell receptor/CD3 complex assembly. The transmembrane domain of the Fc gamma RIIIA alpha subunit forms noncovalent interactions with the comparable domain of the zeta subunit and is sufficient for surface expression of the Fc gamma RIIIA complex. In the absence of these interactions, sequences in the transmembrane domain of the Fc gamma RIIIA alpha subunit signal its degradation. Leu-46, present in the transmembrane domain of the human zeta subunit, is important for assembly with the Fc gamma RIIIA alpha subunit. Substitution of this leucine with an isoleucine, as found in the mouse zeta subunit, significantly reduces this interaction. In contrast, the mouse and human zeta subunits interact with the pentameric T-cell receptor/CD3 complex, resulting in surface expression of this receptor.

Amino Acid Sequence↗

PubMed1988

Purification methods for the sequence-specific DNA-binding protein nuclear factor I (NFI)--generation of protein sequence information.

The paper describes a potent purification method, preparative gel retention, for the purification of sequence-specific DNA-binding proteins. This procedure exploits the sequence-specific DNA-binding affinity of such proteins for their enrichment, comparable to recognition site DNA affinity chromatography. The method was employed to obtain a pure preparation of nuclear factor I (NFI) from porcine liver from which sequences of partial peptides could be obtained. Oligonucleotide probes derived from these amino-acid sequences were used to identify genomic and cDNA clones of NFI.

Amino Acid Sequence↗

PubMed1988

Isolation and characterization of the porcine nuclear factor I (NFI) gene.

This study describes the isolation of a major portion of the gene for nuclear factor I (NFI) including its 5'-flanking region with transcriptional start sites. We screened a porcine liver, genomic DNA library in phage EMBL3A with synthetic oligonucleotides derived from tryptic and cyanogen-bromide peptide sequences obtained from purified NFI protein. The NFI gene is present as a single copy in porcine DNA.

Amino Acid Sequence↗

PubMed1988

A quantitative analysis of nuclear factor I/DNA interactions.

Nuclear factor I (NFI) was purified to homogeneity from porcine liver by DNA-affinity chromatography and displays a single band with a molecular weight of 36 kDa in SDS-polyacrylamide gels. The purified protein was used to determine absolute equilibrium binding constants by gel retardation techniques for a variety of DNA fragments with genuine or mutated NFI binding sites and a number of DNA fragments derived from various eukaryotic promoters carrying the CCAAT-box as a half-site for NFI binding. We present a model which allows prediction of the functional significance of mutated NFI binding-sites from sequence data. The data suggest that the single molecular species of NFI from porcine liver may not be able to recognize and activate the -CCAAT- promoter element in vivo without additional interactions, e.g. with other proteins.

Adenoviridae↗

PubMed1986

A sensitive and rapid gel retention assay for nuclear factor I and other DNA-binding proteins in crude nuclear extracts.

The paper describes a rapid and sensitive assay for DNA binding proteins which interact with specific and defined binding sites. It exploits the observation that complexes of proteins and small synthetic DNA fragments (40 bp) containing the protein/DNA binding site can enter native polyacrylamide gels and remain stably associated during electrophoresis under non-denaturing conditions. The assay was applied to nuclear factor I, to its identification and purification from porcine liver, to an analysis of its binding site on adenovirus type 5 DNA and to an exploration of other potential binding sites for DNA binding proteins within the inverted terminal repetition of adenovirus DNA. The extreme sensitivity of the assay which surpasses that of conventional footprint assays by at least two orders of magnitude permitted the identification of nuclear factor I-like activities in Saccharomyces cerevisiae.

Animals↗

PubMedDate not supplied

Prevalence of peripheral and autonomic neuropathy in newly diagnosed type II (noninsulin-dependent) diabetes.

Type II (noninsulin-dependent) diabetes (NIDDM) can be preceded by a relatively long period of disturbed glucose metabolism. Therefore, the prevalence of neuropathy and its possible relationship to metabolic abnormalities were investigated in 95 newly diagnosed type II diabetics (upper age limit was set at 55 years) with a mean age of 49.7 years (men/women ratio 1:1). The study program was as follows: Detailed history, clinical investigation of peripheral nerves, sensory assessment to touch and pain (pinprick), vibration sensation using established techniques, and motor nerve conduction velocities (MNCV) of the fibular (peroneal) and ulnar nerves. Three cardiovascular autonomic function tests were performed: the Valsalva maneuver, standing (ratio between RR-intervalmax: RR-intervalmin), and deep breathing (maximum/minimum heart rate). Vascular diseases were diagnosed using a conventional 12-lead resting electrocardiogram (ECG) and impedance measurement of the lower extremities. The results were as follows: abnormal vibration sensation in 80.0%, abnormalities of MNCV in 15.7%, abnormal sensations to touch or pinprick in 14.7%, and loss of reflexes in 13.6%. If peripheral neuropathy was defined as having at least three of the four abnormalities plus neuropathic symptoms, the prevalence was 6.3% (6 of 95 patients). Abnormalities of the three cardiovascular autonomic function tests were much less prevalent in type II diabetic patients (2.1-7.3%). In conclusion, the study showed that peripheral and autonomic neuropathy is not common at diagnosis in middle-aged type II diabetic patients without signs of microvascular or macrovascular complications.

Autonomic Nervous System Diseases↗