Search PubMed⌕ Search

Biomedical subjects

A Ullrich

Publications and source records attributed to A Ullrich.

At least 379 records · Page 21Linked to original sources
PubMed1985

Gene for human insulin receptor: localization to site on chromosome 19 involved in pre-B-cell leukemia.

Consistent chromosomal translocations in neoplastic cells may alter the expression of proto-oncogenes that are located near the breakpoints. The complementary DNA sequence of the human insulin receptor is similar to those of the EGF receptor (erbB oncogene) and products of the src family of oncogenes. With in situ hybridization and Southern blot analysis of somatic cell hybrid DNA, the human insulin receptor gene was mapped to the distal short arm of chromosome 19 (bands p13.2----p13.3), a site involved in a nonrandom translocation in pre-B-cell acute leukemia.

Animals↗
PubMed1985

Antibodies against a synthetic peptide as a probe for the kinase activity of the avian EGF receptor and v-erbB protein.

The transforming protein v-erbB of avian erythroblastosis virus (AEV) displays extensive sequence homology with the presumptive protein-tyrosine kinase domain of the human EGF receptor and with the src protein-tyrosine kinase family of oncogenes. However, no kinase activity has previously been demonstrated for the v-erbB protein. Here antibodies generated against a synthetic peptide from the C terminus of human EGF receptor are shown to immunoprecipitate the EGF receptor from human and avian cells, as well as the v-erbB proteins from AEV-transformed cells that become phosphorylated on tyrosine residues upon the addition of gamma-32P-ATP. The immunoprecipitates are also able to phosphorylate exogenous tyrosine-containing substrates. Hence, it is likely that both avian EGF receptor and v-erbB proteins are protein tyrosine-specific protein kinases. Since the kinase activity of v-erbB protein cannot be regulated by EGF, it is proposed that the tyrosine protein kinase function of v-erbB may be constitutively activated.

Alpharetrovirus↗
PubMed1985

Lithium effects on ophthalmological-electrophysiological parameters in young healthy volunteers.

The effects of lithium on the visual system in man have been tested. Ten healthy volunteers followed a 10-day lithium regimen. Lithium plasma levels in the range of 0.6-0.8 mmol/l were obtained. Clinically used ophthalmological-electrophysiological tests were performed. Most of the tests showed no significant change during the lithium treatment. The lithium regimen resulted in a strong reduction of the slow phase. Also the "Arden-ratio", measured by electrooculogram (EOG), was influenced by lithium. The "Arden-ratio" reflects the corneo-fundal potential in retinal illumination and dark adaptation and is influenced by the state of adaptation. All the demonstrated effects were fully reversible at the end of lithium administration. Possible mechanisms of the action of lithium are discussed (for example Ca2+-fluxes, c-AMP, cGMP). These lithium-induced effects on the visual system in man may give some hint of the individual responsiveness to lithium.

Adult↗
PubMed1985

Amplification and overexpression of the EGF receptor gene in primary human glioblastomas.

The expression of epidermal growth factor (EGF) receptor in brain tumours of glial origin was studied at the protein, mRNA and genomic levels. Four out of 10 glioblastomas that overexpress EGF receptor also have gene amplification. The amplified genes appear to be rearranged, generating an aberrant mRNA in at least one of these tumours. Such receptor defects may be relevant to tumorigenesis of human glioblastomas.

Brain Neoplasms↗
PubMed1984

Mouse 7S nerve growth factor: complete sequence of a cDNA coding for the alpha-subunit precursor and its relationship to serine proteases.

Two synthetic oligonucleotides, one 14-mer and one 15-mer, each containing 32 sequences and corresponding to two regions of the partially determined protein sequence, were utilized to identify three cDNA clones coding for the precursor of the alpha-subunit of 7S mouse nerve growth factor (NGF). This library, containing 860 clones, had been preselected from a much larger one by low-stringency hybridization using a cDNA probe corresponding to one of the large family of glandular kallikreins expressed in the adult male mouse submandibular gland. Partial sequence analysis had previously established the alpha-subunit to be a member of this group, albeit with no demonstrable catalytic activity. Nucleotide sequence analysis of the longest of these clones (2A4) predicted the apparent complete amino acid sequence of the 265-residue precursor. One of the other clones (3F2) contained an A----G substitution at position 565 resulting in a Lys----Glu change at position 160 of the mature sequence. These clones probably represent two different alleles. Several amino acid changes, relative to other serine proteases, are evident, which may account for the apparent lack of enzymatic activity. An Arg----Gln substitution at residue -1 would prevent cleavage of the putative activation peptide, and the deletion of residues 2-5 interrupts the highly conserved Ile/Val-Ile/Val-Gly-Gly N-terminal sequence. An Asp----Tyr substitution in the binding pocket and a Gly----His substitution near the active site serine also probably contribute to the inactive structure. The role of this subunit in NGF function remains obscure.

Amino Acid Sequence↗
PubMed1984

Isolation of the human insulin-like growth factor I gene using a single synthetic DNA probe.

A single synthetic oligonucleotide was employed as hybridization probe to detect and enable isolation of the human insulin-like growth factor I (IGF-I) gene from a human genomic DNA library. The synthetic oligonucleotide probe coded for the B-chain of IGF-I and was designed for expression in Escherichia coli. Despite numerous interspersed mismatches, the synthetic probe hybridized specifically with seven recombinant lambda phage containing almost the entire B-chain region of the human IGF-I gene. The usefulness of this approach was further demonstrated by the detection of lambda phage containing human preproinsulin, using A and B chain synthetic oligonucleotides, 90 and 63 nucleotides in length, as hybridization probes. The nucleotide sequence of the human IGF-I exon suggests that IGF-I is synthesized as a larger precursor molecule.

Amino Acid Sequence↗
PubMed1984

The c-sis gene encodes a precursor of the B chain of platelet-derived growth factor.

The relationship between platelet-derived growth factor (PDGF) and the proto-oncogene c-sis has been determined by amino acid sequence analysis of PDGF and nucleotide sequence analysis of c-sis genomic clones. The nucleotide sequences of five regions of the human c-sis gene which are homologous to sequences of the transforming region (v-sis) of simian sarcoma virus (SSV) were determined. By alignment of the c-sis and v-sis nucleotide sequences the predicted amino acid sequence of a polypeptide homologous to the putative transforming protein p28sis of SSV was deduced. Both predicted sequences use the same termination codon and additional coding sequences may lie 5' to the homologous regions. Amino acid sequence analysis of the PDGF B chain shows identity to the amino acid sequence predicted from the c-sis sequences over 109 amino acid residues. Polymorphism may exist at two amino acid residues. These results suggest that c-sis encodes a polypeptide precursor of the B chain. A partial amino acid sequence of the PDGF A chain is also described. This chain is 60% homologous to the B chain and cannot be encoded by that part of c-sis which has been sequenced but could be encoded by sequences which lie 5' to the five regions of v-sis homology in c-sis, or at a separate locus.

Amino Acid Sequence↗
PubMed1984

Structural gene for beta-nerve growth factor not defective in familial dysautonomia.

The developmental loss of neurons in sympathetic, sensory, and some parasympathetic ganglia in familial dysautonomia suggests an inherited defect in the action of beta-nerve growth factor (beta-NGF). The role of this growth factor in dysautonomia has been difficult to resolve as there is no known source of authentic human beta-NGF. The availability of a cloned DNA probe for the human beta-NGF gene has allowed identification of some copies of the gene (alleles) in six affected families. Alleles differ in the length of restriction endonuclease fragments that hybridize to DNA probes for the gene. In two families, affected children did not inherit the same two alleles at the beta-NGF locus. Since this disease is transmitted in an autosomal recessive manner, affected children must share the same alleles at the locus causing the disease. This analysis excludes the beta-NGF gene region as the cause of this neurologic disease but does not eliminate other genes involved in beta-NGF action, such as those coding for processing enzymes, receptors, or other subunits of the NGF complex.

Alleles↗
PubMed1984

Isolation of a cDNA clone coding for the gamma-subunit of mouse nerve growth factor using a high-stringency selection procedure.

A new approach was taken to isolate a full-length cDNA encoding the gamma-subunit of nerve growth factor (NGF). An oligonucleotide probe was used first to identify kallikrein-related sequences in a cDNA library derived from male mouse submaxillary gland mRNA. Of 10,000 clones, 860 were identified as being kallikrein-related; these were analyzed further by hybridization to synthetic oligonucleotides using a procedure which eliminates the effects of base composition and thus allows distinction between partial and perfect sequence complementarity. Nine clones hybridized with a gamma-subunit-specific probe at high stringency, and the nucleotide sequence of the longest cDNA insert was determined. Regions of homology and variability within the kallikrein gene family are maintained in this protein and probably reflect the similar functions and different substrates for this family of proteins.

Amino Acid Sequence↗
PubMed1983

The human gene for the beta subunit of nerve growth factor is located on the proximal short arm of chromosome 1.

Fragments of the recently cloned human gene for the beta subunit of nerve growth factor (beta-NGF) were used as hybridization probes in analyzing two sets of rodent-human somatic cell hybrids for the presence of human beta-NGF sequences. Results from the first set of hybrids assigned the human beta-NGF gene to chromosome 1 and ruled out the presence of sequences of comparable homology on any other chromosome. With the second set of hybrids, which contained seven different, but overlapping, regions of chromosome 1, the NGF locus was mapped to band 1p22.

Animals↗
PubMed1983

Human beta-nerve growth factor gene sequence highly homologous to that of mouse.

Nerve growth factor (NGF) is thought to have a profound effect on the development and maintenance of sympathetic and embryonic sensory neurones (see refs 1-3 for review). NGF activity isolated from the male mouse submaxillary gland (MSG) consists of three types of subunits, alpha, beta and gamma, which specifically interact to form a 7S, approximately 130,000-molecular weight (Mr) complex. The 7S complex contains two identical 118-amino acid beta-chains, which are solely responsible for the nerve growth-stimulating activity of NGF. While NGF is found in almost all vertebrates, most research has focused on murine NGF, as the mouse male submaxillary gland contains higher levels of this polypeptide than other tissues. Even so, beta-NGF comprises only approximately 0.1% of the protein in this small gland, which has made the study of this polypeptide difficult. The amino acid sequence of the mouse NGF beta-chain has been determined and some information has been obtained regarding the size of a mouse precursor molecule, pro-beta-NGF, but little was known about the structure and relatedness of beta-NGF from other vertebrates. Here we describe the isolation of mouse beta-NGF complementary DNA (cDNA) and present its nucleotide sequence, which predicts a prepro-beta-NGF molecule of Mr 27,000 (27K) and a pro-beta-NGF molecule of Mr 25K. We have used the mouse beta-NGF cDNA clone to isolate the human beta-NGF gene, the coding regions of which are highly homologous to the mouse prepro-beta-NGF nucleotide and amino acid sequences.

Animals↗
PubMed1983

Beta-globin locus is linked to the parathyroid hormone (PTH) locus and lies between the insulin and PTH loci in man.

Using a parathyroid hormone (PTH) cDNA probe we found a common Pst I polymorphic restriction site 3' to the PTH gene in all ethnic groups examined. Because the PTH, insulin, and beta-globin loci have been localized to the short arm of chromosome 11 (11p) we used DNA polymorphisms adjacent to each of these three loci to determine whether they are genetically linked and to determine their order. We found that the PTH and beta-globin loci are closely linked (estimated recombination fraction, 0.07; 95% confidence limits, 0.05-0.10; lod score, 4.63; odds favoring linkage, 42,000:1). Furthermore, our findings strongly indicate that the beta-globin gene cluster lies between the PTH and insulin loci. Therefore, the gene order on 11p is centromere-PTH-beta-globin-insulin.

Chromosomes, Human, 6-12 and X↗
PubMed1982

Changes in extracellular potassium and calcium in rat cerebellar cortex related to local inhibition of the sodium pump.

Extracellular K+, Ca2+, and Na+ ([K+]e, [Ca2+]e, [Na+]e) were recorded with ion selective microelectrodes in the cerebellar cortex of urethane-anesthetized rats. Superfusion of the cerebellum with artificial cerebrospinal fluid containing K-strophanthidin (10(-6)-10(-4) mol/l) or other cardioactive steroids, known to be inhibitors of the sodium/potassium pump, had the following effects: elevation of resting [K+]e, reduction of poststimulus K+-undershoots, decrease of resting [Ca2+]e and [Na+]e. For instance, at 3 X 10(-5) mol/l K-strophanthidin within the superfusion solution (the unknown intracerebellar concentration being certainly much smaller), [K+]e was elevated up to 130% and [Ca2+]e reduced to 70% of their resting values. Iontophoretic K+-pulses were enhanced in amplitude at the same time. Control experiments with iontophoretic TMA application demonstrated that the glycoside effects were not due (or in higher concentrations only partly due) to shrinkage of the extracellular fluid volume. When tetrodotoxin (10(-7) mol/l) or Mn2+ (1-3 mmol/l) were additionally superfused, K-strophanthidin effects were qualitatively similar, though quantitatively smaller. This indicates that part of the effects were indirect via neuronal activity evoked by the blockade of the sodium pump. The experiments show that reduction of sodium pump activity in cerebellar cortex has rapid and serious consequences on the distribution of potassium and calcium in the extracellular space, resulting in an alteration of neuronal circuit excitability.

Animals↗
PubMed1982

Variation in the sequence and modification state of the human insulin gene flanking regions.

The nucleotide sequence of a highly repetitive sequence region upstream from the human insulin gene is reported. The length of this region varies between alleles in the population, and appears to be stably transmitted to the next generation in a Mendelian fashion. There is no significant correlation between the length of this sequence and two types of diabetes mellitus. We observe variation in the cleavability of a BglI recognition site downstream from the human insulin gene, which is probably due to variable nucleotide modification. This presumed modification state appears not to be inherited, and varies between tissues within an individual and between individuals for a given tissue. Both alleles in a given tissue DNA sample are modified to the same extent.

Alleles↗