D22S15--a fetal brain cDNA with BanII and SacI RFLP.
Explore the source record for details and available documents.
Brain↗
Biomedical subjects
R L Neve
Publications and source records attributed to R L Neve.
Protease inhibitor domain encoded by an amyloid protein precursor mRNA associated with Alzheimer's disease.
Amyloid B-protein/amyloid A4 is a peptide present in the neuritic plaques, neurofibrillary tangles and cerebrovascular deposits in patients with Alzheimer's disease and Down's syndrome (trisomy 21) and may be involved in the pathogenesis of Alzheimer's disease. Recent molecular genetic studies have indicated that amyloid protein is encoded as part of a larger protein by a gene on human chromosome 21 (refs 6-9). The amyloid protein precursor (APP) gene is expressed in brain and in several peripheral tissues, but the specific biochemical events leading to deposition of amyloid are not known. We have now screened complementary DNA libraries constructed from peripheral tissues to determine whether the messenger RNA encoding APP in these tissues is identical to that expressed in brain, and we identify a second APP mRNA that encodes an additional internal domain with a sequence characteristic of a Kunitz-type serine protease inhibitor. The alternative APP mRNA is present in both brain and peripheral tissues of normal individuals and those with Alzheimer's disease, but its pattern of expression differs from that of the previously reported APP mRNA.
Alzheimer Disease↗
Expression of the Alzheimer amyloid precursor gene transcripts in the human brain.
An alternate form of the Alzheimer amyloid protein precursor mRNA that encodes a protease inhibitor domain has recently been reported. Oligonucleotide probes that differentiate between the two mRNAs are used to describe the expression of each amyloid precursor transcript in the human brain. RNA blot analyses show that one of the mRNAs is expressed selectively in the nervous system, that the two messages display different regional distributions in the adult human brain, and that the expression of the two mRNAs is differentially affected in Down's syndrome brain and in Alzheimer's disease frontal cortex. In situ hybridization shows that the two transcripts display the same laminar distribution in the adult cortex but that the transcripts differ significantly in their levels of expression in pyramidal cells of the hippocampus.
Adult↗
Human GAP-43: its deduced amino acid sequence and chromosomal localization in mouse and human.
The growth-associated protein (GAP-43) is considered a crucial component of an effective regenerative response in the nervous system. Its phosphorylation by protein kinase C correlates with long-term potentiation. Sequence analysis of human cDNAs coding for this protein shows that the human GAP-43 gene is highly homologous to the rat gene; this homology extends into the 3'-untranslated region. However, the human protein contains a 10 amino acid insert. Somatic cell hybrids demonstrate localization of the GAP-43 gene to human chromosome 3 and to mouse chromosome 16.
Amino Acid Sequence↗
Growth-associated protein GAP-43 is expressed selectively in associative regions of the adult human brain.
GAP-43 is a neuron-specific phosphoprotein that has been linked with the development and functional modulation of synaptic relationships. cDNAs for the human GAP-43 gene were used to reveal high overall levels of GAP-43 mRNA in a number of integrative areas of the neocortex, but low levels in cortical areas involved in the initial processing of sensory information, in several brainstem structures, and in caudate-putamen. Neurons expressing highest levels of GAP-43 mRNA were found by in situ hybridization to be concentrated in layer 2 of association cortex and in hippocampal pyramidal cells. Control studies showed that several other RNAs had regional distributions that were different from GAP-43, although the mRNA encoding the precursor of the Alzheimer amyloid beta protein followed a similar pattern of expression. These results suggest that a restricted subset of cortical and hippocampal neurons may be specialized for synaptic remodeling and might play a role in information storage in the human brain.
Association Learning↗
Nerve growth factor increases mRNA levels for the prion protein and the beta-amyloid protein precursor in developing hamster brain.
Deposition of amyloid filaments serves as a pathologic hallmark for some neurodegenerative disorders. The prion protein (PrP) is found in amyloid of animals with scrapie and humans with Creutzfeldt-Jakob disease; the beta protein is present in amyloid deposits in Alzheimer disease and Down syndrome patients. These two proteins are derived from precursors that in the brain are expressed primarily in neurons and are membrane bound. We found that gene expression for PrP and the beta-protein precursor (beta-PP) is regulated in developing hamster brain. Specific brain regions showed distinct patterns of ontogenesis for PrP and beta-PP mRNAs. The increases in PrP and beta-PP mRNAs in developing basal forebrain coincided with an increase in choline acetyltransferase activity, raising the possibility that these markers might be coordinately controlled in cholinergic neurons and regulated by nerve growth factor (NGF). Injections of NGF into the brains of neonatal hamsters increased both PrP and beta-PP mRNA levels. Increased PrP and beta-PP mRNA levels induced by NGF were confined to regions that contain NGF-responsive cholinergic neurons and were accompanied by elevations in choline acetyltransferase. It remains to be established whether or not exogenous NGF acts to increase PrP and beta-PP gene expression selectively in forebrain cholinergic neurons in the developing hamster and endogenous NGF regulates expression of these genes.
Amyloid↗
A C-terminal, calmodulin-like regulatory domain from the plasma membrane Ca2+-pumping ATPase.
A cDNA that encodes what appears to be the inhibitory domain of the plasma membrane calcium-pumping ATPase (Ca2+-ATPase) has been isolated by screening a lambda gt11 bovine brain cDNA library with antibodies prepared against the human erythrocyte membrane Ca2+-ATPase. This screening resulted in isolation of a bacteriophage containing a 1.5-kilobase cDNA insert encoding a 71-residue polypeptide, the remainder being a large 3' terminal noncoding region. A portion of this deduced peptide sequence was identical to that of a peptide isolated from a V8 protease digest of the human erythrocyte Ca2+-ATPase except for 1 residue. Antibodies purified by immunoabsorption to the fusion protein containing this cDNA-encoded polypeptide reacted only with those fragments of a limited trypsin digest of the human erythrocyte Ca2+-ATPase that contain the inhibitory domain. Moreover, these antibodies were able to partially stimulate basal enzyme activity and block further activation by calmodulin. The encoded polypeptide bears homology to the glutamic acid-rich regions N-terminal to the Ca2+-binding loops of calmodulin and to a lesser extent with the loops themselves. This encoded polypeptide also represents the C terminus of the Ca2+-ATPase. Portions of the isolated cDNA were homologous to the 3' noncoding region of the sarcoplasmic reticulum Ca2+-ATPase cDNA, indicating a possible mechanism for the evolution of these distinct membrane Ca2+ pumps.
Amino Acid Sequence↗
Partial sequence of MAP2 in the region of a shared epitope with Alzheimer neurofibrillary tangles.
A 3.3-kilobase DNA complementary to human microtubule-associated protein 2 (MAP2) was sequenced by the dideoxy method. The 3' end terminates at an internal EcoRI site before the polyA tail. Due to the arrangement of the cDNA insert in the lambda gt11 vector, the MAP2 fragment is not fused to beta-galactosidase when expressed. The Chou Fasman algorithm for the initial 58 amino acids from the first in-frame methionine predicts an alpha helix. Beyond this point, a series of turns is predicted until amino acid 160. The frequent presence of basic residues in proximity to serines or threonines is consistent with multiple phosphorylation sites. The minimum specificity determinant for Ca2+/calmodulin-dependent kinase is repeated 13 times. The sequence of a region containing a MAP2 epitope that is shared with the Alzheimer neurofibrillary tangle was determined by DNase treatment of the cDNA and antibody selecting the small resultant clones in a lambda gt11 sublibrary. Likewise, a MAP2 epitope that is not shared with the neurofibrillary tangle also has been located. Both epitopes are in the projection portion of the molecule. A bovine MAP2 cyanogen bromide fragment, which contains the epitope shared with the neurofibrillary tangle, is partially insoluble under aqueous conditions, probably due to the aggregation of oppositely charged residues. Thus, rapid cleavage of MAP2 to small peptides is probably necessary in vivo to prevent the aggregation of larger cleavage fragments.
Alzheimer Disease↗
Absence of duplication of chromosome 21 genes in familial and sporadic Alzheimer's disease.
The possibility that Alzheimer's disease (AD) is caused by overexpression or duplication of one or more genes on chromosome 21 has been raised by the observation of AD-like neuropathologic changes in individuals with Down syndrome and by the mapping of both the defect for familial AD and the amyloid beta protein gene to this autosome. Possible duplication on chromosome 21 was investigated in both familial and sporadic AD by means of restriction fragment length polymorphisms for the amyloid and SODI loci, as well as for DNA markers in the vicinity of the familial AD defect and in the critical Down syndrome region of chromosome 21. No evidence of increased DNA dosage was observed in either brain or leukocytes of patients with inherited or sporadic forms of AD. Duplication of these regions is therefore not a frequent event in either form of AD. Furthermore, no significant allelic association was detected between AD and any of the loci, including the amyloid and SODI genes, providing no support for the hypothesis that defects in these specific genes are the primary cause of AD.
Alleles↗
The amyloid beta protein gene is not duplicated in brains from patients with Alzheimer's disease.
Complementary DNAs (cDNAs) encoding portions of the amyloid beta protein were used to investigate possible amyloid gene duplication in sporadic Alzheimer's disease. A strategy employing two Eco RI restriction fragment length polymorphisms (RFLPs) detected by the amyloid cDNAs was used. RFLPs allow the detection of a 2:1 gene dosage in the DNA of any individual who is heterozygous for a particular RFLP. The amyloid gene regions homologous to the cDNAs used were not duplicated in the DNA from brains of individuals with sporadic Alzheimer's disease. Similar results were also obtained with a strategy employing a test for 3:2 gene dosage.
Alleles↗
Amyloid beta protein gene: cDNA, mRNA distribution, and genetic linkage near the Alzheimer locus.
The amyloid beta protein has been identified as an important component of both cerebrovascular amyloid and amyloid plaques of Alzheimer's disease and Down syndrome. A complementary DNA for the beta protein suggests that it derives from a larger protein expressed in a variety of tissues. Overexpression of the gene in brain tissue from fetuses with Down syndrome (trisomy 21) can be explained by dosage since the locus encoding the beta protein maps to chromosome 21. Regional localization of this gene by both physical and genetic mapping places it in the vicinity of the genetic defect causing the inherited form of Alzheimer's disease.
Alzheimer Disease↗
The neuronal growth-associated protein GAP-43 (B-50, F1): neuronal specificity, developmental regulation and regional distribution of the human and rat mRNAs.
The protein that has been designated as GAP-43, B-50, F1 or pp46 is associated with the growth and modulation of neuronal connections. cDNA clones for the rat and human genes were isolated and used to demonstrate that the messenger RNA for the protein is expressed only in neurons, that its overall level is highest in the developing brain, and that in the adult human brain levels of the mRNA are highest in the associative neocortex.
Animals↗
A somatic cell hybrid with a single human chromosome 22 corrects the defect in the CHO mutant (Ade-I) lacking adenylosuccinase activity.
Adenine-requiring Chinese hamster ovary (CHO-K1) auxotrophs of the complementation group Ade-I were hybridized with various human cells, and hybrids were isolated under selective conditions in which retention of the complementing gene on the human chromosome is necessary for survival. Ade-I cells are deficient in adenylosuccinase activity. This enzyme carries out two independent, but similar, steps of purine biosynthesis: the removal of a fumarate from succinylaminoimidazole carboxamide ribotide to produce aminoimidazole carboxamide ribotide and the removal of fumarate from adenylosuccinate to produce AMP. These are the 9th and 13th steps of adenylate biosynthesis, respectively. Analysis of hybrids by cytogenetics and by Southern blot techniques using chromosome 22-specific DNA probes, one of which encodes an antigen expressed in human fetal brain, indicated that human chromosome 22 was 100% concordant for growth without adenine. One hybrid subclone, isolated after two successive rounds of subcloning, was found to be capable of growth without adenine; the only human chromosome present was 22. In addition, segregants that had lost the ability to grow in adenine-free media had also lost human chromosome 22. These results suggest that the human gene for adenylosuccinase resides on chromosome 22.
Adenylosuccinate Lyase↗
Molecular structure of chromosome 21.
Explore the source record for details and available documents.
Chromosome Mapping↗
McArdle's & Hers' diseases: glycogen phosphorylase transcriptional expression in human tissues.
We have cloned the cDNA encoding human liver glycogen phosphorylase (glycogenosis type VI) from a fetal brain cDNA library. Liver(L) and muscle(M) phosphorylase cDNA probes were used to determine the relative abundance of mRNA encoding the L- and M-isozymes of phosphorylase in human fetal and adult tissues. The transcript encoding the M-isozyme is 3.4 kb; the L-isozyme transcript is 3.3 kb. Transcriptional expression of the L-isozyme in human and primate tissues was found to differ from the isozyme's reported tissue specificity in non-primate mammals. Furthermore, using degenerate oligonucleotide probes to two different coding regions of M-phosphorylase, a novel 4.1-kb transcript was demonstrated to be present in human fetal and adult brain.
Amino Acid Sequence↗
A cDNA for a human microtubule associated protein 2 epitope in the Alzheimer neurofibrillary tangle.
Microtubule associated protein 2 (MAP2) forms a long outward projection from the microtubule wall and is localized to the microtubule population of neuronal cell bodies and dendrites. In Alzheimer's disease, MAP2 epitopes are shared with the neurofibrillary tangle (NFT). Direct information about the molecular composition of the NFT can be obtained by cloning the genes for protein epitopes shared with NFT. Using two monoclonal antibodies to distinct MAP2 epitopes, one of which recognizes NFT, we screened a complex human fetal brain cDNA expression library constructed in lambda gt11. A 2.4 kilobase (kb) cDNA reacted with both antibodies independently. Northern blot analysis showed hybridization of the clone to a 9 kb RNA specific not only to brain but also to neurons. The DNA sequence of the cDNA will include the information for the MAP2 epitope contained in NFT.
Alzheimer Disease↗
Identification of cDNA clones for the human microtubule-associated protein tau and chromosomal localization of the genes for tau and microtubule-associated protein 2.
We have previously identified a partial human cDNA for MAP2, and we now report the isolation of human cDNA clones for tau. The RNA species recognized by the tau clones is a 6 kilobase (kb) message that is expressed in the human brain but not in other human tissues, and exhibits a developmental shift in size. We also report the human chromosomal localization of the MAP2 and tau genes. The MAP2 cDNA pKN7 was used to localize the MAP2 gene to chromosome 2q34-35. The tau cDNAs were used to confirm the presence of a tau gene on chromosome 17q21 and an additional region of homology on chromosome 6p21.
Chromosome Mapping↗
Human chromosome 21-encoded cDNA clones.
We have employed two strategies to isolate random cDNA clones encoded by chromosome 21. In the first approach, a cDNA library representing expressed genes of WA17, a mouse-human somatic cell hybrid carrying chromosome 21 as its sole human chromosome, was screened with total human DNA to identify human chromosome 21-specific cDNAs. The second approach utilized previously characterized single-copy genomic fragments from chromosome 21 as probes to retrieve homologous coding sequences from a human fetal brain cDNA library. Six cDNA clones on chromosome 21 were obtained in this manner. Two were localized to the proximal long arm of chromosome 21, two to the distal portion of the long arm, and one to the region of 21q22 implicated in the pathology of Down syndrome.
Chromosome Mapping↗