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At least 127 records · Page 7Linked to original sources

A novel gene order in the Paracentrotus lividus mitochondrial genome.

The mitochondrial DNA (mtDNA) from Paracentrotus lividus (sea urchin) eggs, a circular molecule of about 15,500 bp, has been cloned in plasmid vectors after cleavage with various restriction enzymes. By a combination of Northern blot hybridization and nucleotide sequence analysis we have characterized most of the P. lividus mitochondrial transcripts and determined the basic gene organization of the mtDNA. The nucleotide sequence of a gene for one NADH dehydrogenase (ND) subunit, ND4L, has also been determined. Our results show the existence of a novel gene order. The 12S and 16S rRNA genes are not contiguous but are separated from each other by ND1 and ND2 genes. The ND4L gene is not adjacent to ND4 but is located between the tRNAArg gene and the gene for subunit II of cytochrome oxidase (CoII). The tRNA genes are reshuffled and contrary to all vertebrate mitochondrial genomes studied so far, there are no intergenic regions between the tRNAPhe and the cytochrome b genes. These characteristics suggest a peculiar mechanism for the regulation of gene expression in this organism and provide information on the evolution of the mitochondrial genetic system in animal cells.

Animals↗

In the QTL region surrounding porcine MHC, gene order is conserved with human genome.

On the porcine genome, the region surrounding the Major Histocompatibility Complex, also called Swine Leukocyte Antigens (SLA), is of particular interest not only owing to itq role in the control of immune response, but also because of its influence on many traits such as growth, fatness, and meat quality. To help in the identification of responsible genes, detailed comparative maps of the MHC region in mammalian species and powerful mapping tools allowing accurate ordering of genes and markers in this region are needed. In this report, we describe the use of the recently developed IMpRH radiation hybrid panel, to construct a higher density radiation hybrid map of swine Sscr 7p-q12, containing 23 additional loci. Our results show that the gene order is conserved between the two MHC-containing regions, even if an inversion is observed above the QTL region in the region containing DEK, SCA1, and EDN1 genes. The framework map produced shows that the IMpRH panel permits the ordering of genes and markers in the three MHC classes and would thus allow accurate localization of ESTs and candidate genes.

Animals↗

The use of random-breakage mapping to locate the genes APN1 and YUH1 in the Saccharomyces genome, and to determine gene order near the left end of chromosome XI.

We have used the previously described technique of random-breakage mapping to locate the two yeast genes APN1 and YUH1. The APN1 locus is located approximately 235 kb from the left telomere of chromosome XI, and shows weak (approximately 53 cM) genetic linkage to ura1. The YUH1 locus is located approximately 140 kb from the right telomere of chromosome X, and genetically maps 3.6 cM distal to cdc11. In addition, we show by random-breakage mapping that TRP3 is located approximately 45 kb from the left telomere of chromosome XI, whereas FAS1 is approximately 110 kb from the same telomere. This supports a gene order on the left distal portion of chromosome XI that agrees with other physical reports but is inverted with respect to Edition 11 of the published genetic map. This report confirms that random-breakage mapping is a rapid and convenient method of locating cloned genes.

Chromosome Mapping↗

The Escherichia coli C homoprotocatechuate degradative operon: hpc gene order, direction of transcription and control of expression.

Homoprotocatechuate (HPC; 3,4-dihydroxyphenylacetate) is catabolized to Krebs cycle intermediates via extradiol (meta-) cleavage and the necessary enzymes are chromosomally encoded in a variety of bacteria. Based on an analysis of the cloned pathway genes, the Escherichia coli C hpc gene cluster was thought to be arranged in two gene blocks transcribed from a central, divergent, operator/promoter region, which was negatively regulated by the Hpc repressor. By a variety of techniques including expression of cloned hpc genes in pUC18/19 vectors, unidirectional deletion subcloning, hybridization studies and nucleotide sequencing it has now been shown that the hpc pathway structural genes are transcribed in one direction. These experiments have also indicated that a decarboxylase and an isomerase of the pathway are encoded by a single gene (hpcE) and have established the exact structural gene order as hpcRphpcECBDGH. The position of the putative regulatory gene, hpcR, is upstream of the first structural gene (hpcE) for the Hpc pathway enzymes. The deduced open reading frame for the Hpc repressor specifies a protein of 148 amino acids with a subunit molecular weight of 17 kDa. The region between hpcR and the first gene for the pathway enzymes has a sequence similar to that for catabolite activator protein (CAP) binding. This region is immediately upstream of a promoter for the pathway structural genes, which has been identified by transcript mapping.

3,4-Dihydroxyphenylacetic Acid↗

Molecular genetic analysis of distal mouse chromosome 6 defines gene order and positions of the deafwaddler and opisthotonos mutations.

Two neurological mutants deafwaddler (dfw) and opisthotonos (opt) and a cluster of three Shaker-like potassium (K) channel genes Kcna1, Kcna5, and Kcna6 were all independently mapped to distal mouse chromosome six (Chr 6). In this study, genetic and molecular techniques were employed to assess directly the linkage of the two mutants and to investigate the likelihood that a mutation in one of the three K channel genes may underlie dfw and/or opt. Genetic crosses testing for allelism showed that the dfw and opt mutations complement each other. Additional crosses demonstrated that the mutants are separated by a recombination distance of 3.1 +/- 1.8 cM. Microsatellite marker analysis of the crossover chromosomes recovered from the opt, dfw recombination study indicated that opt maps centromeric to dfw. The location of the K channel genes relative to the dfw mutation was determined by mapping these genes and 15 microsatellite markers in an intersubspecific backcross (IB) segregating for dfw [(CAST/Ei-+/+ x C3HeB/FeJ-dfw/dfw) x C3HeB/FeJ-dfw/dfw]. Analysis of the backcross progeny positioned the dfw locus in the interval between the microsatellite markers D6Mit11 and D6Mit55, D6Mit63. The K channel cluster maps telomeric to dfw. This study establishes the gene order cen-opt-dfw-Rho (D6Mit44)-Kcna1, Kcna5, Kcna6 on distal mouse Chr 6 and suggests that the neurological mutants opt and dfw affect two different genes, neither of which is caused by a mutation in any one of the three clustered K channels.

Animals↗

Sequence analysis of the 22K, SH and G genes of turkey rhinotracheitis virus and their intergenic regions reveals a gene order different from that of other pneumoviruses.

The nucleotide and deduced amino acid sequences of three genes of turkey rhinotracheitis virus (TRTV) together with the nucleotide sequences of the relevant intergenic regions were determined. The deduced amino acid sequence of one of the genes shows significant identity (42%) to that of the 22K protein of human respiratory syncytial virus (RSV). The TRTV 22K gene, like that of RSV, has a second open reading frame, although the amino acid sequence deduced from this reading frame does not show any similarity to the equivalent predicted RSV protein. The other two genes and their deduced amino acid sequences do not show any sequence similarity to the genes of other pneumoviruses. However, the hydrophobicity profiles of the predicted proteins do show similarities to those of the small hydrophobic (SH) and attachment protein (G) genes of RSV. The TRTV G gene is 1193 nucleotides in length and encodes a protein of 391 amino acids (M(r) 42984), which is rather larger than the RSV G protein (predicted M(r) 36000). The TRTV SH gene is 589 nucleotides in length, encoding a protein of 174 amino acids (M(r) 18797), which is considerably larger than the size of the RSV SH protein (M(r) 7500). The sequences of the intergenic regions derived from clones of polycistronic mRNAs and polymerase chain reaction products obtained with primers from different genes reveal the order on the virus genome to be 3' F-22K-SH-G 5'. This differs from the gene order of paramyxoviruses and morbilliviruses, which lack a 22K gene (and in some cases a SH gene), and the pneumoviruses RSV and pneumonia virus of mice, which have the F and 22K genes located after the G gene.

Amino Acid Sequence↗

Identification of plu genes and cis-acting elements of PCNA in the Drosophila genus using conservation of gene order.

In Drosophila melanogaster, the cell cycle control gene, plutonium (plu), is located between the PCNA and RpS18 genes at position 56F on chromosome arm 2R. We have used a comparative genomic approach to investigate the evolution of the plu gene and to locate conserved cis-acting elements for plu, RpS18 and PCNA. Using primers within coding regions of PCNA and RpS18, we amplified and sequenced the intervening region from twelve Drosophila species. In each species, this region contains a plu gene resembling the D. melanogaster gene in size and in the number and position of introns. The predicted Plu sequence from the different species demonstrates that the first two ankyrin repeats are conserved. Of the transcriptional control elements of D. melanogaster PCNA, we found that three motifs 5' to the PCNA transcription unit are conserved in Drosophila species.

Amino Acid Sequence↗

Similarities of ordered gene lists.

MOTIVATION: Many applications of microarray technology in clinical cancer studies aim at detecting molecular features for refined diagnosis. In this paper, we follow an opposite rationale: we try to identify common molecular features shared by phenotypically distinct types of cancer using a meta-analysis of several microarray studies. We present a novel algorithm to uncover that two lists of differentially expressed genes are similar, even if these similarities are not apparent to the eye. The method is based on the ordering in the lists. RESULTS: In a meta-analysis of five clinical microarray studies we were able to detect significant similarities in five of the ten possible comparisons of ordered gene lists. We included studies, where not a single gene can be significantly associated to outcome. The detection of significant similarities of gene lists from different microarray studies is a novel and promising approach. It has the potential to improve upon specialized cancer studies by exploring the power of several studies in one single analysis. Our method is complementary to previous methods in that it does not rely on strong effects of differential gene expression in a single study but on consistent ones across multiple studies.

Algorithms↗

Exceptional conservation of horse-human gene order on X chromosome revealed by high-resolution radiation hybrid mapping.

Development of a dense map of the horse genome is key to efforts aimed at identifying genes controlling health, reproduction, and performance. We herein report a high-resolution gene map of the horse (Equus caballus) X chromosome (ECAX) generated by developing and typing 116 gene-specific and 12 short tandem repeat markers on the 5,000-rad horse x hamster whole-genome radiation hybrid panel and mapping 29 gene loci by fluorescence in situ hybridization. The human X chromosome sequence was used as a template to select genes at 1-Mb intervals to develop equine orthologs. Coupled with our previous data, the new map comprises a total of 175 markers (139 genes and 36 short tandem repeats, of which 53 are fluorescence in situ hybridization mapped) distributed on average at approximately 880-kb intervals along the chromosome. This is the densest and most uniformly distributed chromosomal map presently available in any mammalian species other than humans and rodents. Comparison of the horse and human X chromosome maps shows remarkable conservation of gene order along the entire span of the chromosomes, including the location of the centromere. An overview of the status of the horse map in relation to mouse, livestock, and companion animal species is also provided. The map will be instrumental for analysis of X linked health and fertility traits in horses by facilitating identification of targeted chromosomal regions for isolation of polymorphic markers, building bacterial artificial chromosome contigs, or sequencing.

Animals↗

Marburg virus, a filovirus: messenger RNAs, gene order, and regulatory elements of the replication cycle.

The genome of Marburg virus (MBG), a filovirus, is 19.1 kb in length and thus the largest one found with negative-strand RNA viruses. The gene order - 3' untranslated region-NP-VP35-VP40-GP-VP30-VP24-L-5' untranslated region-resembles that of other non-segmented negative-strand (NNS) RNA viruses. Six species of polyadenylated subgenomic RNAs, isolated from MBG-infected cells, are complementary to the negative-strand RNA genome. They can be translated in vitro into the known structural proteins NP, GP (non-glycosylated form), VP40, VP35, VP30 and VP24. At the gene boundaries conserved transcriptional start (3'-NNCUNCNUNUAAUU-5') and stop signals (3'-UAAUUCUUUUU-5') are located containing the highly conserved pentamer 3'-UAAUU-5'. Comparison with other NNS RNA viruses shows conservation primarily in the termination signals, whereas the start signals are more variable. The intergenic regions vary in length and nucleotide composition. All genes have relatively long 3' and 5' end non-coding regions. The putative 3' and 5' leader RNA sequences of the MBG genome resemble those of other NNS RNA viruses in length, conservation at the 3' and 5' ends, and in being complementary at their extremities. The data support the concept of a common taxonomic order Mononegavirales comprising the Filoviridae, Paramyxoviridae, and Rhabdoviridae families.

Base Sequence↗

Physical mapping of the murine casein locus reveals the gene order as alpha-beta-gamma-epsilon-kappa.

The murine casein locus has been characterized by long-range restriction mapping and the analysis of large fragment genomic clones. Cloned sequences from five mouse casein genes (alpha, beta, gamma, epsilon, kappa) were used to screen a murine (strain 129) genomic library in a bacterial artificial chromosome vector (BAC). Of the nine clones isolated, two contained three casein genes alpha, beta, gamma and gamma, epsilon, kappa, respectively. The following combinations were found in other clones: alpha + beta, beta + gamma; and gamma + epsilon. Thus, the gene order in the locus can be deduced to be alpha-beta-gamma-epsilon-kappa. This order was confirmed by restriction analysis of the clones. A contig map of the clones and flanking sequences has been established by characterizing seven BAC clones, which together span approximately 470 kb. Long-range restriction analysis of genomic DNA indicates that the murine casein locus is confined to a 250-kb partial Xho I fragment. The alpha and beta casein genes were shown to be arranged in a tail-to-tail orientation.

Animals↗

The complete mitochondrial DNA sequence of the bichir (Polypterus ornatipinnis), a basal ray-finned fish: ancient establishment of the consensus vertebrate gene order.

The evolutionary position of bichirs is disputed, and they have been variously aligned with ray-finned fish (Actinopterygii) or lobe-finned fish (Sarcopterygii), which also include tetrapods. Alternatively, they have been placed into their own group, the Brachiopterygii. The phylogenetic position of bichirs as possibly the most primitive living bony fish (Osteichthyes) made knowledge about their mitochondrial genome of considerable evolutionary interest. We determined the complete nucleotide sequence (16,624 bp) of the mitochondrial genome of a bichir, Polypterus ornalipinnis. Its genome contains 13 proteincoding genes, 22 tRNAs, two rRNAs and one major noncoding region. The genome's structure and organization show that this is the most basal vertebrate that conforms to the consensus vertebrate mtDNA gene order. Bichir mitochondrial protein-coding and ribosomal RNA genes have greater sequence similarity to ray-finned fish than to either lamprey or lungfish. Phylogenetic analyses suggest the bichir's placement as the most basal living member of the ray-finned fish and rule out its classification as a lobefinned fish. Hence, its lobe-fins are probably not a shared-derived trait with those of lobe-finned fish (Sarcopterygii).

Amino Acid Sequence↗

The gene orders on human chromosome 15 and chicken chromosome 10 reveal multiple inter- and intrachromosomal rearrangements.

Comparative mapping between the human and chicken genomes has revealed a striking conservation of synteny between the genomes of these two species, but the results have been based on low-resolution comparative maps. To address this conserved synteny in much more detail, a high-resolution human-chicken comparative map was constructed from human chromosome 15. Mapping, sequencing, and ordering of specific chicken bacterial artificial chromosomes has improved the comparative map of chromosome 15 (Hsa15) and the homologous regions in chicken with almost 100 new genes and/or expressed sequence tags. A comparison of Hsa15 with chicken identified seven conserved chromosomal segments between the two species. In chicken, these were on chromosome 1 (Gga1; two segments), Gga5 (two segments), and Gga10 (three segments). Although four conserved segments were also observed between Hsa15 and mouse, only one of the underlying rearrangement breakpoints was located at the same position as in chicken, indicating that the rearrangements generating the other three breakpoints occurred after the divergence of the rodent and the primate lineages. A high-resolution comparison of Gga10 with Hsa15 identified 19 conserved blocks, indicating the presence of at least 16 intrachromosomal rearrangement breakpoints in the bird lineage after the separation of birds and mammals. These results improve our knowledge of the evolution and dynamics of the vertebrate genomes and will aid in the clarification of the mechanisms that underlie the differentiation between the vertebrate species.

Animals↗

Effects of altered gene order or orientation of the locus control region on human beta-globin gene expression in mice.

The five human beta-type-globin genes, epsilon, Ggamma, Agamma, delta and beta, are close together and are regulated by a locus control region (LCR) located at the 5' end of the locus. Here we investigate the functional consequences of this organization with respect to temporal regulation of the individual genes, by using recombination techniques to invert the order of either the genes or the LCR in vivo. Our analysis of transgenic mice bearing either normal or mutant transgenes leads to two new observations. First, the position of the epsilon-globin gene next to the LCR is mandatory for its expression during the yolk-sac stage of erythropoiesis. Second, LCR activity is orientation dependent, and so the LCR does not act as a simple enhancer to stimulate transcription of the globin genes. Thus, in the absence of any change in transgene integration position, transgene copy number, trans-acting factors or other resident genetic information, simple inversion of the human genes or the LCR fundamentally alters the transcription of beta-type globin genes.

Animals↗

Big trees from little genomes: mitochondrial gene order as a phylogenetic tool.

Gene arrangement comparisons are a powerful tool for phylogenetic studies, especially those focused on ancient relationships. Recent reports using metazoan mitochondrial genomes address evolutionary relationships as well as rates and mechanisms of rearrangement. Mitochondrial systems serve as a model for larger-scale comparisons of whole organismal genomes and a stimulus for developing methods for reconstructing the patterns of rearrangement.

Animals↗

Incipient mitochondrial evolution in yeasts. I. The physical map and gene order of Saccharomyces douglasii mitochondrial DNA discloses a translocation of a segment of 15,000 base-pairs and the presence of new introns in comparison with Saccharomyces cerevisiae.

We have determined the physical and genetic map of the 73,000 base-pair mitochondrial genome of a novel yeast species Saccharomyces douglasii. Most of the protein and RNA-coding genes known to be present in the mitochondrial DNA of Saccharomyces cerevisiae have been identified and located on the S. douglasii mitochondrial genome. The nuclear genomes of the two species are thought to have diverged some 50 to 80 million years ago and their nucleo-mitochondrial hybrids are viable but respiratorily deficient. The mitochondrial genome of S. douglasii displays many interesting features in comparison with that of S. cerevisiae. The three mosaic genes present in both genomes are quite different with regard to their structure. The S. douglasii COXI gene has two new introns and is missing the five introns of the S. cerevisiae gene. The S. douglasii cytochrome b gene has one new intron and lacks two introns of the S. cerevisiae gene. Finally, the L-rRNA gene of S. douglasii, like that of S. cerevisiae, has one intron of which the structure is different. Another salient feature of the S. douglasii mitochondrial genome reported here is that the gene order is different in comparison with S. cerevisiae mitochondrial DNA. In particular, a segment of approximately 15,000 base-pairs including the genes coding for COXIII and S-rRNA has been translocated to a position between the genes coding for varl and L-rRNA.

Adenosine Triphosphatases↗