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At least 721 records · Page 40Linked to original sources

Isolation, characterization, and mapping of four novel polymorphic markers and an H3.3B pseudogene to chromosome 9p21-22.

Alterations in chromosomal region 9p21-22 are among the most frequently encountered cytogenetic changes present in a number of human malignancies. In addition, the causative genes of a number of hereditary cancers have been genetically mapped to this region. We describe the isolation and precise localization of four novel polymorphic markers and a previously identified marker, D9S1846, from this region. Moreover, we have identified a retroposon-rich area within this oncogenic region containing a processed H3.3B pseudogene flanked by an L1 sequence and an Alu element. Together, these finely mapped and ordered reagents should prove useful for genetic mapping, sequencing, and loss of heterozygosity studies of the 9p21-22 region.

Base Sequence↗

A new confirmatory Neisseria gonorrhoeae real-time PCR assay targeting the porA pseudogene.

The Roche Cobas Amplicor system is widely used for the detection of Neisseria gonorrhoeae but is known to cross react with some commensal Neisseria spp. Therefore, a confirmatory test is required. The most common target for confirmatory tests is the cppB gene of N. gonorrhoeae. However, the cppB gene is also present in other Neisseria spp. and is absent in some N. gonorrhoeae isolates. As a result, laboratories targeting this gene run the risk of obtaining both false-positive and false-negative results. In the study presented here, a newly developed N. gonorrhoeae LightCycler assay (NGpapLC) targeting the N. gonorrhoeae porA pseudogene was tested. The NGpapLC assay was used to test 282 clinical samples, and the results were compared to those obtained using a testing algorithm combining the Cobas Amplicor System (Roche Diagnostics, Sydney, Australia) and an in-house LightCycler assay targeting the cppB gene (cppB-LC). In addition, the specificity of the NGpapLC assay was investigated by testing a broad panel of bacteria including isolates of several Neisseria spp. The NGpapLC assay proved to have comparable clinical sensitivity to the cppB-LC assay. In addition, testing of the bacterial panel showed the NGpapLC assay to be highly specific for N. gonorrhoeae DNA. The results of this study show the NGpapLC assay is a suitable alternative to the cppB-LC assay for confirmation of N. gonorrhoeae-positive results obtained with Cobas Amplicor.

DNA, Bacterial↗

Determination of genetic sex in chinook salmon (Oncorhynchus tshawytscha) using the male-linked growth hormone pseudogene by real-time PCR.

This study used a real-time quantitative polymerase chain reaction (qPCR) method based on the growth hormone pseudogene (GHp) in chinook salmon (Oncorhynchus tshawytscha) to determine genetic sex. The GHp is present as a single copy in the genome of the male chinook salmon but is absent in the female, providing a means of using this real-time qPCR method to discriminate genetic sex. Comparisons between genomic DNA samples from 2 geographically distinct populations of chinook salmon (Columbia River, Washington, and Yukon River, Alaska) showed, within each population examined, that the males were clearly differentiated from the females. There were no interpopulation differences between males or females. The advantages of this real-time qPCR method are that it is rapid, is amenable to high sample throughput, and provides an accurate numerical value that allows comparisons between samples by statistical methods.

Alaska↗

Cholesterol 7 alpha hydroxylase promoter separated from cyclophilin pseudogene by Alu sequence.

The promoter for human cholesterol 7-alpha hydroxylase has been cloned and sequenced. In the regions previously described, our sequence agrees well with one report but not with another. At position -469, we find a widespread MaeII polymorphism. At -2636, there is an Alu sequence flanked by runs of adenines. Upstream of the Alu sequence, there is a cyclophilin pseudogene oriented in the opposite direction.

Amino Acid Isomerases↗

The characterization of three types of partially processed mRNA and two pseudogenes for human liver cytochrome b5.

We have isolated cDNA clones corresponding to partially processed human liver cytochrome b5 mRNAs. All the clones contained poly(A) sequences, and one clone had a shorter 3' non-translated sequence, indicating the use of an alternative poly(A) addition signal. In addition, all the clones contained the coding information for amino acids 87-134; however, there were two types of intron junction adjacent to the coding sequence. Detailed analysis of the Type I clones showed that the Type II intron sequence was contained within the Type I sequence, but approximately 1000 bp 5' of the Type I intron-exon junction showed alternative splicing within this intron. In addition, we have isolated two pseudogenes which lack introns, suggesting the retroviral insertion of human liver cytochrome b5 mRNA sequences into the human genome.

Amino Acid Sequence↗

Identification in human genomic DNA of the sequence homologous but not identical to either the histo-blood group ABH genes or alpha 1----3 galactosyltransferase pseudogene.

Based on polymerase chain reaction (PCR) and sequencing of the cloned amplified fragments, we identified a homologous sequence to the histo-blood group ABH genes and alpha 1----3 galactosyltransferase pseudogene. The presence of this sequence in human genomic DNA was confirmed by Southern hybridization.

ABO Blood-Group System↗

The human serum amyloid A locus SAA4 is a pseudogene.

We have isolated the human genomic DNA clone GSAA4 from a size-selected Bgl II library by hybridization to a probe derived from the human serum amyloid A gene GSAA1. Sequencing the 5' end of this clone revealed a region similar to the first exon of gene GSAA1 but with significant nucleotide differences and mutation of the 3' splice site. The restriction map of the GSAA4 clone corresponds to that for the locus "SAA4" recently reported by others. Sequence and hybridization details indicate that the locus in clone GSAA4 is a member of the human serum amyloid A gene family and contains a pseudogene. Isolating GSAA4 completes the collection of clones needed to account for all bands found in blot hybridizations of human DNA using serum amyloid A gene probes.

Base Sequence↗

Vacuolar type H(+)-ATPase genes: presence of four genes including pseudogenes for the 16-kDa proteolipid subunit in the human genome.

Genes for the human vacuolar type H(+)-ATPase proteolipid (16-kDa) subunit were cloned and their nucleotide sequences were determined. Comparison of the deduced sequences indicated that at least four genes including pseudogenes are present in the human genome. One of them corresponded to that for the 16-kDa subunit expressed in HeLa cells. The coding sequence was separated by two introns. The second intron was located in the DNA segment giving a loop between the second and third transmembrane helices, supporting the idea that the 16-kDa subunit was evolved by gene duplication. The primary sequence determined from the second clone had a termination codon behind the third transmembrane helix. Possible translation products from the other two clones had no putative acidic residues essential for proton transport function of the 16-kDa subunit. Thus, it is interesting to know whether these genes are transcribed, since they may have unique cellular functions.

Base Sequence↗

Identification of four genomic loci highly related to casein-kinase-2-alpha cDNA and characterization of a casein kinase-2-alpha pseudogene within the mouse genome.

Using the coding region of the human CK-2 alpha cDNA as a probe for screening a genomic mouse library, positive clones representing four different genomic loci were isolated. Partial DNA sequences of these loci encompassing the first 120 nucleotides of the putative coding region are reported. One positive clone was further analyzed by sequencing a 3.1 kb XbaI fragment. This clone displays the characteristics of a pseudogene, i.e. lack of introns and several nucleotide insertions and deletions. In its 3' region it contains a 91 bp large CT-rich stretch which consists of (CCTT) and (CT) repeats; in the 5' region three (CCCCCT) repeats.

Animals↗

The second human beta B2-crystallin gene is a pseudogene.

Comparison of the partial sequences of the human beta B2-1- and beta B2-2-crystallin genes with orthologous rat or calf sequences shows that the fourth exon sequence of the human beta B2-2 gene contains a one triplet deletion and a mutated splice acceptor site. No transcripts from the beta B2-2-crystallin gene could be detected in the human lens. These data suggest that the human beta B2-2-crystallin gene is a pseudogene.

Base Sequence↗

Human peripheral blood lymphocytes express D5 dopamine receptor gene and transcribe the two pseudogenes.

Sequential reverse transcription and polymerase chain reaction (RT-PCR) of the mRNA were used to investigate the expression of dopamine receptors in human peripheral blood lymphocytes. The RT-PCR products contained three types of sequences, each corresponding to those of the D5 dopamine receptor gene and the two related pseudogenes. The lymphocyte cDNA library also contained the clones encoding parts of the three genes. Binding profiles of dopaminergic ligands to the lymphocytes were similar to those for the native neuronal membranes.

Benzazepines↗

Structural comparison of the yeast cell division cycle gene CDC4 and a related pseudogene.

The function of the cell division cycle gene, CDC4, is required in Saccharomyces cerevisiae for progression beyond the G1 phase of the cell cycle. The wild-type gene was isolated from a plasmid library by selection for complementation of a recessive, temperature-sensitive allele. Hybridization of genomic sequences with the cloned gene revealed the presence of a duplicated sequence. Both CDC4 and the duplicated sequence were subjected to DNA sequence analysis. These analyses revealed (1) that CDC4 contains a large open reading frame encoding a protein of 779 amino acids, and (2) that the duplicated sequence bears strong homology with the carboxy-terminal segment of this open reading frame. Presence of a nonsense codon within the duplicated sequence suggested that it does not encode a functional product. Disruption of the duplicated sequence within the yeast genome provided a more critical test for function. The absence of any detectable phenotype for this disruption confirms that the sequence should be considered a pseudogene. The marker inserted to disrupt the sequence also served to map the duplication and to establish that it is not genetically linked to CDC4. The structural features determined suggest evolutionary relationships between these genes as well as between the CDC4 product and other proteins.

Base Sequence↗

Acyl-CoA-binding protein/diazepam-binding inhibitor gene and pseudogenes. A typical housekeeping gene family.

Acyl-CoA-binding protein (ACBP) is a 10 kDa protein isolated from bovine liver by virtue of its ability to bind and induce the synthesis of medium-chain acyl-CoA esters. Surprisingly, it turned out to be identical to a protein named diazepam-binding Inhibitor (DBI) claimed to be an endogenous modulator of the GABAA receptor in brain membranes. ACBP/DBI, or proteolytically derived polypeptides of ACBP/DBI, have also been implicated in the control of steroidogenesis in mitochondria and glucose-stimulated insulin secretion. Thus, it appears that ACBP/DBI is a remarkable, versatile protein. Now we have molecularly cloned and characterized the ACBP/DBI gene family in rat. The rat ACBP/DBI gene family comprises one expressed gene and four processed pseudogenes of which one was shown to exist in two allelic forms. The expressed gene is organized into four exons and three introns. There is a remarkable correspondence between the structural modules of ACBP/DBI as determined by 1H nuclear magnetic resonance spectroscopy and the exon-intron architecture of the ACBP/DBI gene. Detailed analyses of transcription of the ACBP/DBI gene in brain and liver were performed to map transcription initiation sites and to examine if transcripts from the ACBP/DBI gene were subject to alternative processing. In both brain and liver, transcription is initiated from two major and multiple minor initiation sites. No evidence for alternative splicing was obtained. The promoter region of the ACBP/DBI gene is located in a CpG island and lacks a canonical TATA box. Thus, the ACDB/DBI gene exhibits all the hallmarks of a typical housekeeping gene.

Animals↗

The human X-linked steroid sulfatase gene and a Y-encoded pseudogene: evidence for an inversion of the Y chromosome during primate evolution.

The mammalian X and Y chromosomes are thought to have evolved from a common, nearly homologous chromosome pair. Although there is little sequence similarity between the mouse or the human X and Y, there are several regions in which moderate to extensive sequence homologies have been found, including, but not limited to, the so-called pseudoautosomal segment, in which X-Y pairing and recombination take place. The steroid sulfatase gene is in the pseudoautosomal region of the mouse, but not in man. We have cloned and characterized the human STS X-encoded locus and a pseudogene that is present on the long arm of the Y chromosome. Our data in humans and other primates suggest that there has been a pericentric inversion of the Y chromosome during primate evolution that has disrupted the former pseudoautosomal arrangement of these genes. These results provide additional insight into the evolution of the sex chromosomes and into the nature of this interesting portion of the human genome.

Animals↗

Sequence of the 24S alpha ribosomal RNA gene and characterization of a corresponding pseudogene from Trypanosoma cruzi.

Two genomic clones which cover a 30-kb region containing the ribosomal RNA cistron from Trypanosoma cruzi have been isolated. The location of the 18S, 24S alpha and 24S beta RNA species within the cistron was determined. The complete sequences of the genes corresponding to the 24S alpha RNA and to a small RNA (S1), as well as two internal transcribed spacers were obtained by sequencing a cDNA and a genomic fragment. A locus containing sequences related to the 24S alpha RNA has been determined. Sequence data and structural characterization of this locus strongly suggest that this region contains a 24S alpha RNA pseudogene.

Animals↗

Sequence homology and absence of mRNA defines a possible pseudogene member of the Trypanosoma cruzi gp85/sialidase multigene family.

A genomic clone, pTt21, containing DNA apparently transcribed specifically in Trypanosoma cruzi trypomastigotes, was obtained by differentially screening a genomic library with trypomastigote and epimastigote cDNA. This 3444-bp clone contained open reading frames at each end, separated by a 1.8-kb non-coding region. The translated polypeptide from the 3' open reading frame (ORF2) of 1037 bp had 25-30% identity with 5 recently published T. cruzi gp85/sialidase sequences, and 20-25% identity with bacterial sialidases. Rabbit antiserum raised against an Escherichia coli fusion protein derived from the 5' open reading frame (ORF1) identified a surface antigen of 160 kDa, specifically expressed in trypomastigotes. A probe containing the first 211 bp from ORF1 was used to obtain a complete copy (c1821) of a gene that was closely related to ORF1, and encoded another member of the gp85/sialidase family. c1821 encodes a protein of 897 amino acids, but assignment of the N-terminus of the polypeptide was not possible. The 5'-most start codon is an unfavourable context to act as a translation initiator, it does not align with the initiator methionines of other gp85/sialidase sequences, nor is it followed by a signal peptide sequence characteristically found in other gp85/sialidase sequences. Although homology with the 5' ends of other gp85/sialidase sequences decays towards the 5' end of c1821, alignment of c1821 with 4 other gp85/sialidases indicated that the coding sequence should extend upstream at least 160 amino acids. In this region of c1821 there are multiple stop codons in each frame. The presence of the stop codons, the alignment data and our inability to amplify reverse transcribed mRNA using four internal primers, suggest that c1821 may not be present as a mature mRNA and is a pseudogene. Comparison of the apparently non-repetitive 3' coding domain of c1821 with the corresponding repetitive domains of two other members of the gp85/sialidase family revealed a high degree of similarity in nucleotide but not in amino acid sequence, and c1821 may thus represent an evolutionary intermediate between sub-families of the gp85/sialidase superfamily.

Amino Acid Sequence↗

Isolation of an active gene and of two pseudogenes for mouse U7 small nuclear RNA.

Three U7 RNA-related sequences were isolated from mouse genomic DNA libraries. Only one of the sequences completely matches the published mouse U7 RNA sequence, whereas the other two apparently represent pseudogenes. The matching sequence represents a functional gene, as it is expressed after microinjection into Xenopus laevis oocytes. Sequence variations of the conserved cis-acting 5' and 3' elements of U RNA genes may partly explain the low abundance of U7 RNA.

Animals↗

Structures of the human cDNA and gene encoding the 78 kDa gastrin-binding protein and of a related pseudogene.

The nucleotide sequence encoding the human 78 kDa gastrin binding protein (GBP) has been deduced from overlapping fragments generated by the polymerase chain reaction with oligonucleotides based on the sequence of the porcine GBP (Mantamadiotis, T. et al. (1993) Biochim. Biophys. Acta 1170, 211-215) and cDNA from the colonic carcinoma cell line LIM 1215 as template. The mature human GBP is 90% identical to the porcine GBP. Clones encoding the human GBP gene, which contains 19 exons, have been isolated from human genomic libraries. The positions of the exon/intron junctions are completely different from the junctions in the gene encoding the related peroxisomal trifunctional enzyme. Clones encoding a related pseudogene have also been isolated and sequenced.

Amino Acid Sequence↗