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PubMed1991

Molecular and genetic analysis of a region of plasmid pCF10 containing positive control genes and structural genes encoding surface proteins involved in pheromone-inducible conjugation in Enterococcus faecalis.

Exposure of Enterococcus faecalis cells carrying the tetracycline resistance plasmid pCF10 to the heptapeptide pheromone cCF10 results in an increase in conjugal transfer frequency by as much as 10(6)-fold. Pheromone-induced donor cells also express at least two plasmid-encoded surface proteins, the 130-kDa Sec 10 protein, which is involved in surface exclusion, and the 150-kDa Asc10 protein, which has been associated with the formation of mating aggregates. Previous subcloning and transposon mutagenesis studies indicated that the adjacent EcoRI c (7.5 kb) and e (4.5 kb) fragments of pCF10 encode the structural genes for these proteins and that the EcoRI c fragment also encodes at least two regulatory genes involved in activation of the expression of the genes encoding Asc10 and Sec10. In this paper, the results of physical and genetic analysis of this region of pCF10, along with the complete DNA sequences of the EcoRI c and e fragments, are reported. The results of the genetic studies indicate the location of the structural genes for the surface proteins and reveal important features of their transcription. In addition, we provide evidence here and in the accompanying paper (S. B. Olmsted, S.-M. Kao, L. J. van Putte, J. C. Gallo, and G. M. Dunny, J. Bacteriol. 173:7665-7672, 1991) for a role of Asc10 in mating aggregate formation. The data also reveal a complex positive control system that acts at distances of at least 3 to 6 kb to activate expression of Asc10. DNA sequence analysis presented here reveals the positions of a number of specific genes, termed prg (pheromone-responsive genes) in this region of pCF10. The genes mapped include prgA (encoding Sec10) and prgB (encoding Asc10), as well as four putative regulatory genes, prgX, -R, -S, and -T. Although the predicted amino acid sequences of Sec10 and Asc10 have some structural features in common with a number of surface proteins of gram-positive cocci, and the Asc10 sequence is highly similar to that of a similar protein encoded by the pheromone-inducible plasmid pAD1 (D. Galli, F. Lottspeich, and R. Wirth, Mol. Microbiol. 4:895-904, 1990), the regulatory genes show relatively little resemblance to any previously sequenced genes from either procaryotes or eucaryotes.

Amino Acid Sequence↗
PubMed1996

The unexpected recovery of hybrids in a Drosophila species cross: a genetic analysis.

The species cross between Drosophila melanogaster and D. simulans was first described by Sturtevant in the 1920s. According to his description, the hybridization of D. simulans females and D. melanogaster males produces only (or almost only) male progeny. Female hybrids are embryonic lethal. Here it is shown that these traditional results no longer hold. Instead, D. simulans is polymorphic for factor(s) that qualitatively affect the outcome of species crosses to D. melanogaster. Remarkably, many, if not most, strains of D. simulans produce abundant female hybrids when crossed to D. melanogaster males. Genetic analysis of the difference between D. simulans strains that produce many versus few hybrid females shows that recovery of hybrid females depends on autosomal, maternally acting gene(s).

Animals↗
PubMed2001

Molecular cloning and genetic analysis of an indole-diterpene gene cluster from Penicillium paxilli.

The indole-diterpene paxilline is a potent tremorgenic mammalian mycotoxin and a known inhibitor of maxi-K ion channels. The gene cluster responsible for paxilline biosynthesis in Penicillium paxilli was identified by mapping four large plasmid-induced chromosome deletions. The cluster is predicted to lie within a 50 kb region of chromosome Va and to contain 17 genes, including a geranylgeranyl pyrophosphate (GGPP) synthase (paxG), two FAD-dependent monooxygenases (paxM and N), two cytochrome P450 monooxygenases (paxP and Q), a dimethylallyltryptophan (DMAT) synthase (paxD) and two possible transcription factors (paxR and paxS), which contain a Zn(II)2Cys6 DNA-binding motif. Targeted replacement of paxG confirmed that it is essential for paxilline biosynthesis but dispensable for growth. The GGPP for primary metabolism is predicted to be provided by a second GGPP synthase (ggs1) that was cloned, sequenced and mapped to chromosome IV. Semi-quantitative reverse transcriptase-polymerase chain reaction analysis demonstrated that the expression of paxG, paxM and paxP in submerged liquid cultures of P. paxilli increased dramatically with the onset of paxilline biosynthesis. In contrast, the expression of beta-tubulin (tub2) and ggs1 was not induced. This is the first description of the molecular cloning and genetic analysis of an indole-diterpene gene cluster.

Alkyl and Aryl Transferases↗
PubMed1984

[Genetic analysis of the Mud mutants of Escherichia coli K-12 with an impaired ability to maintain bacteriophage Mu development].

Properties of mud mutations affecting intracellular development of bacteriophage Mu have been studied. We demonstrate pleiotropy of these mutations as well as their effect on the development of Mu-like heteroimmune D108 phage and P1 phage, on the ability to inherit Mu prophage within the chromosome during conjugation, and the abortive inheritance of chromosomal markers during P1 transduction. Experimental evidence is given to support the concept that the effect of the mutations has no relation to the mutants' impaired ability to adsorb the phages. Genetic analysis which involved conjugational crossings using different Hfr donors and F' plasmids made it possible to localize the mud-1 mutation between ilv and metE genes in the region of 84-85 min of the Escherichia coli K-12 genetic map. The nature of mutations and a possible functional role of the mud-impaired gene is discussed.

Chromosome Mapping↗
PubMed2006

[The discovery and genetic analysis of dwarf mutation 99CDAM in Brassica napus L].

The plant height of rapeseed varieties has increased more than 20 cm due to wide application of heterosis, which leads to high risk of lodging at late stages of rapeseed development. Using dwarf genes to decrease plant height is an effective approach to resolve the lodging problem. A dwarf mutation 99CDAM with plant height of about 85 cm was discovered from a Brassica napus line which had selfed for many years. The mutation 99CDAM has good characters of early flowering and rich branches, as well as better yield and quality traits, which can be stably inherited, so 99CDAM has important value in Brassica napus breeding. Genetic analysis on reciprocal crosses between 99CDAM with high-stalk lines 2091, 7045 and 7350, and the F2BC1 and F2:3 populations derived from the cross between 2091 with 99CDAM indicated that the genetic model of dwarf genes in 99CDAM was obviously different from what had been reported before. The mutation 99CDAM was controlled by three pairs of recessive dwarf genes and showed a maternal effect..

Brassica napus↗
PubMed2006

Notch receptor encodes two structurally separable functions in Drosophila: a genetic analysis.

The Notch gene of Drosophila encodes a single transmembrane receptor that plays a central role in the process of lateral inhibition. This process results in the selection of individual mesodermal and neural precursors during the development of the muscular and nervous systems. The activation of Notch during lateral inhibition is mediated by the transmembrane ligand Delta (Dl) and effected by the transcription factor Suppressor of Hairless (Su(H)). The same functional cassette plays a role in other processes, in particular, the development and patterning of the wing. Genetic analysis has suggested that, in addition to the Su(H)-dependent pathway, Notch can signal in an Su(H)-independent manner. This process seems to be tightly associated with signalling by Wingless, a member of the Wnt family of signalling molecules. Here, we have analyzed further the possibility that the Notch protein encodes two different functions. To do so, we have studied the activities and genetic properties of different Notch receptors bearing deletions of specific regions of the intracellular and the extracellular domains in different developmental processes, and have sought to correlate the activity of these mutant proteins with those of existing mutants in Notch. Our results support the existence of at least two different activities of Notch each of which can be associated with specific structural domains.

Animals↗
PubMed2000

Genetic analysis of insulin-like growth factor II and HLA-G in pre-eclampsia.

Pre-eclampsia (PE) is uniquely a disease of pregnancy and is the major cause of foetal and maternal morbidity and mortality. Epidemiological studies show that PE is highly heritable, with a high incidence in all populations. The underlying pathology indicates that absent or shallow invasion of foetal trophoblasts into maternal arteries is a feature of true PE. The objective of this study was to determine the genetic factors influencing PE. A large number of mother-father-baby trios were collected in which the first pregnancy was complicated by severe PE. After careful examination of the epidemiology and pathology of the disease, two plausible candidate genes, namely insulin-like growth factor II (IGF-II) and HLA-G, were analysed for association with PE. No association was found between a commonly occurring polymorphism in IGF-II and PE. Three polymorphisms in HLA-G were analysed in the sample cohorts. No association was found between three polymorphisms in HLA-G and PE. However, the frequency of the HLA-G insertion/deletion polymorphism in exon 8 deviated significantly from Hardy-Weinberg expectations in PE off-spring, reflecting an excess of heterozygotes for these polymorphisms in PE offspring. The significance of this deviation is not clear and further genetic analysis will be necessary to confirm this finding and to explore further the candidacy of HLA-G in PE.

Adult↗
PubMed2005

[Genetic analysis and mapping of the rice leafy-hull mutant Oslh].

Oslh (lh=leafy hull), in the japonica cultivar 9522 background, a mutant of Oryza sativa L. spp. japonica cv. 9522 identified from an M(2) population, was mutagenized by irradiation with (60)Co gamma-ray. The Oslh mutant plants flowered about 15 days later than the wild-type plants (Fig.1e). The paleas, lemmas and lodicules of the flowers of Oslh mutant were transformed into leaf-like structures (Fig.1b, d). Genetic analysis of the F(2) progeny from a cross between the Oslh mutant and wild-type japonica cv. 9522 revealed that the Oslh mutant arouse from a single recessive nuclear gene mutation of the cv. 9522. To map the Oslh locus, an F(2) population generated by crossing between Oslh (japonica) mutant and Guangluai4 (indica) was analyzed. The Oslh locus was mapped to the long arm of rice chromosome 3, between a SSR marker RM5475 and an InDel marker GY305, 2.9 and 1.5 cM away from these two markers respectively (Fig.4). These results are useful for further cloning and functional analysis of the OsLH gene.

Chromosome Mapping↗
PubMed2005

[Genetic analysis of anthocyanin of the anthers and culm pigmentation in common wheat].

Anthocyanin pigmentation of various organs develops during plant ontogeny in response to adverse and damaging abiotic and biotic stressors (environmental factors). Using the monosome method, the genes responsible for anther and culm anthocyanin pigmentation (Pan1 and Pc2, respectively) were localized to 7D chromosome in introgressive lines from crosses between common wheat Triticum aestivum L. and the species Triticum timopheevii Zhuk. Genetic analysis of ten common wheat genotypes using testers carrying genes Pan1, Pn1, and Pn2 showed that these genotypes contained Pan1 and Pn2 genes. Visual examination of plants from 70 and 76 varieties of respectively winter and spring common wheat revealed anthocyanin pigmentation of anthers and culms in 36 varieties. Pan1 and Pn2 genes were presumably introduced into common wheat from Aegilops tauschii (Fig.) Tzvel., a donor of the D genome.

Chromosomes, Plant↗
PubMedDate not supplied

Genetic analysis of variation for auxin-induced adventitious root formation among eighteen ecotypes of Arabidopsis thaliana L. Heynh.

Eighteen ecotypes and two inbred lines of Arabidopsis thaliana L. Heynh. were analyzed for variation in the number of adventitious roots formed (hereafter referred to as rooting) on seedling hypocotyls in response to auxin treatment. Mean root counts varied from 1.7 to 23.1. Stable high (HA) and low (LA) rooting lines selected from ecotype Columbia, a low rooting ecotype (Mt-0), and unselected Columbia populations were evaluated for vegetative and reproductive growth parameters to determine correlated phenotypic effects of selection for rooting response. High rooting in HA correlated with compact, highly branched shoot growth. Genetic analysis of HA, Mt-0, and their F1, F2, and reciprocal backcross generations indicated that high and low rooting responses in this population may be controlled by several genes acting independently in additive-dominance fashion. Genetic variance partitioned into principally additive effects, with dominance favoring low rooting.

Arabidopsis↗
PubMedDate not supplied

Genetic analysis and characterization of poly(aspartic acid) hydrolase-1 from Sphingomonas sp. KT-1.

Sphingomonas sp. KT-1 hydrolyzes poly(aspartic acid) (PAA) containing alpha- and beta-amide units and has at least two different types of PAA hydrolases. The PAA hydrolase-1 hydrolyzes selectively beta-beta amide units in PAA. Molecular cloning of PAA hydrolase-1 from Sphingomonas sp. KT-1 has been carried out to characterize its gene products. Genetic analysis shows that the deduced amino acid sequence of PAA hydrolase-1 has a similarity with those of the catalytic domain of poly(3-hydroxybutyric acid) (PHB) depolymerases from Alcaligenes faecalis AE122 and Pseudomonas lemoignei. Site-specific mutation analysis indicates that (176)Ser is a part of a strictly conserved pentapeptide sequence (Gly-Xaa-Ser-Xaa-Gly), which is the lipase box, and plays as an active residue.

Amino Acid Sequence↗
PubMed1997

Genetic analysis of the phi X174 DNA binding protein.

The phi X174 J protein is 37 amino acids in length and contains 12 basic residues. There are no acidic amino acids in the protein. The basic residues are concentrated in two clusters in the N-terminus which are separated by a proline-rich region. To investigate the morphogenetic functions of the J protein and possible mechanisms by which it may bind DNA, a genetic analysis was conducted. Lysine --> leucine and arginine --> leucine substitutions were generated within the basic amino acid clusters. At least three substitutions were required to eliminate viability in vivo. Lethal mutants with three or four substitutions exhibit dominant lethal phenotypes, indicating that the mutant proteins retain enough function to interfere with productive assembly. In cells infected with a dominant lethal mutant, noninfectious packaged particles were produced. Infectivity can be restored by second-site suppressors in the viral coat protein which disrupt polar interactions atop the threefold axis of symmetry in the capsid. The viability of strains containing compensating frameshift mutations within the proline-rich region suggests that only the proline residues in this segment are critical for efficient function.

Amino Acid Sequence↗
PubMed1981

Generation of lipopolysaccharide-induced interferon in spleen cell cultures. I. Genetic analysis and cellular requirements.

Incubation of murine spleen-cell cultures with lipopolysaccharide (LPS) induces interferon (IF) production. Maximal IF levels are obtained after incubation with 100 microgram/ml for 10 h. Two inbred mouse strains differing in their ability to generate LPS-induced IF in spleen-cell cultures were used: C3H/eB, which generates high levels of IF (about 60 units/ml), and C3H/HeJ, which fails to generate detectable quantities of IF. In a genetic analysis these strains were hybridized and IF production was determined in spleen-cell cultures from F1 and F2 generations, and from backcrosses of F1 hybrids to parent strains. The results indicate that, in parent strains, a single dominant autosomal gene is responsible for differences in IF production in spleen cultures. LPS-induced IF in spleen-cell cultures resists pH 2 for as long as 48 h, but is labile to heating at 56 degrees C for 30 min. Both macrophages and lymphocytes must be present in cultures for generation of LPS-induced IF. By using mixed cultures of macrophages and lymphocytes from C3H/eB and C3H/HeJ mice, it was shown that macrophages have to interact directly with LPS to enable IF production in the cultures.

Animals↗
PubMed2006

Genetic analysis of skeletal dysplasia: recent advances and perspectives in the post-genome-sequence era.

Skeletal dysplasia is a group of disorders of the skeleton that result from derangement of growth, development and/or differentiation of the skeleton. Nearly 300 disorders are included; most of them are monogenic diseases. Responsible genes for skeletal dysplasia have been identified in more than 150 diseases mainly through positional cloning. Identification of disease genes would improve patient care through genetic diagnosis as well as improving our understanding of the diseases and molecular mechanism of skeletal tissue formation. Studies of skeletal dysplasia would also help identify disease genes for common diseases affecting bones and joints. In this study, the author reviews recent advances and the current status of the genetic analysis of skeletal dysplasia and its impacts on research into skeletal biology.

Bone Diseases, Developmental↗
PubMed1990

Tn1000-mediated insertion mutagenesis of the histidine utilization (hut) gene cluster from Klebsiella aerogenes: genetic analysis of hut and unusual target specificity of Tn1000.

The histidine utilization (hut) genes from Klebsiella aerogenes were cloned in both orientations into the HindIII site of plasmid pBR325, and the two resulting plasmids, pCB120 and pCB121, were subjected to mutagenesis with Tn1000. The insertion sites of Tn1000 into pCB121 were evenly distributed throughout the plasmid, but the insertion sites into pCB120 were not. There was a large excess of Tn1000 insertions in the "plus" or gamma delta orientation in a small, ca. 3.5-kilobase region of the plasmid. Genetic analysis of the Tn1000 insertions in pCB120 and pCB121 showed that the hutUH genes form an operon transcribed from hutU and that the hutC gene (encoding the hut-specific repressor) is independently transcribed from its own promoter. The hutIG cluster appears not to form an operon. Curiously, insertions in hutI gave two different phenotypes in complementation tests against hutG504, suggesting either that hutI contains two functionally distinct domains or that there may be another undefined locus within the hut cluster. The set of Tn1000 insertions allowed an assignment of the gene boundaries within the hut cluster, and minicell analysis of the polypeptides expressed from plasmids carrying insertions in the hut genes showed that the hutI, hutG, hutU, and hutH genes encode polypeptides of 43, 33, 57, and 54 kilodaltons, respectively.

Cloning, Molecular↗
PubMed2003

Clinical features and genetic analysis of a Chinese kindred with Fabry's disease.

BACKGROUND: Fabry's disease is an X-linked recessive inborn error of glycosphingolipid catabolism resulting from deficient activity of lysosomal enzyme alpha-galactosidase A causing occlusive microvascular diseases affecting the kidney, heart, peripheral nerves and brain. It is an uncommon disease in the Oriental population. METHODS AND RESULTS: We report a Chinese kindred of Fabry's disease and the relevant clinical features are discussed. The diagnosis of Fabry's disease was based on serum alpha-galactosidase A activity and typical histological features from renal biopsy in the index patient. Genetic analysis of two hemizygous male patients revealed a missense mutation predicting a leucine to proline substitution (L14P) in the alpha-galactosidase gene causing classical Fabry's disease in this family. This is a novel point mutation not described previously in the literature and the second report describing novel genetic mutations for Fabry's disease in Chinese patients. CONCLUSIONS: Fabry's disease is rare in Chinese patients but this diagnosis should be considered in patients with positive family history of kidney disease and relevant clinical features.

Adult↗
PubMedDate not supplied

Molecular genetic analysis of multi-drug resistance in Indian isolates of Mycobacterium tuberculosis.

A total of 116 isolates from patients attending the out-patient department at the All India Institute of Medical Sciences, New Delhi and the New Delhi Tuberculosis Centre, New Delhi, India were collected. They were analyzed for resistance to drugs prescribed in the treatment for tuberculosis. The drug resistance was initially determined by microbiological techniques. The Bactec 460TB system was employed to determine the type and level of resistance in each isolate. The isolates were further characterized at molecular level. The multi-drug loci corresponding to rpo beta, gyr A, kat G were studied for mutation(s) by the polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) technique. The SSCP positive samples were sequenced to characterize the mutations in rpo beta, and gyr A loci. While previously reported mutations in the gyr A and rpo beta loci were found to be present, several novel mutations were also scored in the rpo beta locus. Interestingly, analysis of the gyr A locus showed the presence of point mutation(s) that could not be detected by PCR-SSCP. Furthermore, rifampicin resistance was found to be an important marker for checking multi-drug resistance (MDR) in clinical isolates of Mycobacterium tuberculosis. This is the first report on molecular genetic analysis of MDR tuberculosis from India, and highlights the increasing incidence of MDR in the Indian isolates of M. tuberculosis.

Humans↗
PubMed2004

[Clinical and pathological significance of the genetic analysis in colorectal carcinomas].

The molecular genetics of colorectal carcinomas are among the best understood of common human cancers. Three inter-related molecular pathways are involved. The chromosomal instability pathway begins with inactivation of the APC/beta-catenin genes followed by activation of oncogenes and inactivation of additional suppressor genes, commonly with high frequency of allelic losses, cytogenetic abnormalities. The microsatellite instability pathway begins with inactivating one of a group of genes responsible for DNA nucleotide mismatch repair leading to extensive mutations in both repetitive and non-repetitive DNA sequences with low frequencies of allelic losses and rare alteration of tumor DNA content. Finally, the CpG island methylation pathway involves inactivation of genes by methylation of cytosines in promoter regions to silence gene expression without DNA sequence alterations. Molecular genetics have the potential for clinical applications. Combination of genetic classification of high levels of microsatellite instability (MSI-H), gene expression analysis of mismatch repair genes and subsequent mutation analysis of inactivated genes can be used as an effective method for the identification of hereditary nonpolyposis colorectal carcinoma patients. Molecular genetic alterations have been proposed to be of prognostic value, including allelic deletion on chromosome 18q, and on chromosome 17p. MSI-H has been reported as a marker for better prognosis. Individualizing chemoradiation by use of predictive markers for response or resistance to therapy is important in patients with advanced disease or candidacy for adjuvant therapy.

Chromosomal Instability↗