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1.
Mutations in COCH that result in non-syndromic autosomal dominant deafness (DFNA9) affect matrix deposition of cochlin 总被引:4,自引:0,他引:4
The COCH gene mutated in autosomal dominant sensorineural deafness (DFNA9) encodes cochlin, a major constituent of the inner ear extracellular matrix. Sequence analysis of cochlin from DFNA9 patients identified five distinct single-amino-acid mutations within a conserved region (the LCCL domain) of cochlin. To define the molecular basis of DFNA9, we have generated myc-tagged wild-type and mutant cochlins and explored their behavior in transient transfection systems. Western blotting of cell lysates and culture media indicates that wild-type and mutant cochlins are synthesized and secreted in similar amounts. Immunofluorescent staining confirms that all are detected within the endoplasmic reticulum and the Golgi complex of transfected cells. Our findings suggest that COCH mutations are unlikely to cause abnormalities in secretion and suggest that extracellular events might cause DFNA9 pathology. In agreement, we show that wild-type cochlin accumulates in extracellular deposits that closely parallel the matrix component fibronectin, whereas mutant cochlins vary in the amount and pattern of extracellular material. Whereas some mutants exhibit an almost normal deposition pattern, some show complete lack of deposition. Our results suggest that DFNA9 results from gene products that fail to integrate correctly into the extracellular matrix. The partial or complete penetrance of integration defects suggests that DFNA9 pathology may be caused by multiple molecular mechanisms, including compromised ability of cochlin to self-assemble or to form appropriate complexes with other matrix components. 相似文献
2.
Ikezono T Shindo S Li L Omori A Ichinose S Watanabe A Kobayashi T Pawankar R Yagi T 《Biochemical and biophysical research communications》2004,314(2):440-446
The COCH gene mutated in DFNA9, an autosomal dominant hereditary sensorineural hearing loss and vestibular disorder, encodes Cochlin. Previously, we reported three bovine Cochlin isoforms, p63s, p44s, and p40s, which exhibit significant molecular heterogeneity in vivo. Here we have characterized Cochlin isoforms by generating four isoform-specific anti-Cochlin antibodies. The same three Cochlin isoforms, p63s, p44s, and p40s, were detected in human and cow inner ear tissue; however, p44s and p40s were not detected in perilymph. We identified a novel short 16kDa isoform in human perilymph and a 18-23kDa isoform in cow perilymph, named Cochlin-tomoprotein (CTP), corresponding to the N-terminus of full-length Cochlin (p63s) and the LCCL domain. Notably, CTP contains all of the known mutation sites associated with DFNA9. The pathogenesis of DFNA9 is not fully clarified as yet, and this novel perilymph-associated CTP isoform might provide mechanistic clues to how mutations in the COCH gene damage the inner ear function. 相似文献
3.
Liepinsh E Trexler M Kaikkonen A Weigelt J Bányai L Patthy L Otting G 《The EMBO journal》2001,20(19):5347-5353
The LCCL domain is a recently discovered, conserved protein module named after its presence in Limulus factor C, cochlear protein Coch-5b2 and late gestation lung protein Lgl1. The LCCL domain plays a key role in the autosomal dominant human deafness disorder DFNA9. Here we report the nuclear magnetic resonance (NMR) structure of the LCCL domain from human Coch-5b2, where dominant mutations leading to DFNA9 deafness disorder have been identified. The fold is novel. Four of the five known DFNA9 mutations are shown to involve at least partially solvent-exposed residues. Except for the Trp91Arg mutant, expression of these four LCCL mutants resulted in misfolded proteins. These results suggest that Trp91 participates in the interaction with a binding partner. The unexpected sensitivity of the fold with respect to mutations of solvent-accessible residues might be attributed to interference with the folding pathway of this disulfide-containing domain. 相似文献
4.
5.
群体凝血因子C同源物基因(Coagulation factor C homology,COCH)是人类发现的第一个伴前庭功能障碍的耳聋基因,位于人类染色体14q12-q13上。迄今,在COCH基因上发现16个位点突变导致常染色体显性遗传非综合征型耳聋DFNA9的发生,其中包括13个非同义单核苷酸多态性(Non-synonymous single nucleotide polymorphisms,nsSNPs)位点。由于该基因其他nsSNPs的基因型与表型关系尚不清楚,因此文章采用生物信息学方法,从COCH基因全部的SNPs中分级筛选,结合已知的致病nsSNPs信息及蛋白三维结构验证,首次预测出由COCH基因编码的cochlin蛋白的vWFA (Von Willebrand factor type A domain)区的8个高风险致病性nsSNPs(I176T、R180Q、G265E、V269L、I368N、I372T、R416C和Y424D)。同时,对位于LCCL (Limulus factor C, cochlin, and late gestation lung protein Lgl1)区域的6个已知致病突变的nsSNPs ( P51S、G87W、I109N、I109T、W117R和F121S)进行了三维结构模拟,发现突变体均发生了环状结构或链状结构的改变。本研究对COCH基因的基因型与表型的相关性研究为遗传性耳聋筛查提供了相应的理论依据,也对该基因所编码的cochlin蛋白的功能研究具有一定的指导意义。 相似文献
6.
N. Uematsu C. Matsuoka Y. Agemizu E. Nagoshi K. Yamamoto 《Molecular & general genetics : MGG》1999,261(3):523-529
The chromosomal tonB gene of Escherichia coli was used as a target for the detection of spontaneous deletion mutations. The deletions were isolated in both recA
+ and recA
− cells, and mutants carrying large deletions were identified because they also lacked part or all of the trp operon. The frequencies of tonB-trp deletion were 1.79 × 10−9 and 1.09 × 10−9 for recA
+ and recA
− cells, respectively. We analyzed 12 deletions from recA
+ and 10 from recA
− cells by cloning and direct sequencing. The deletions ranged in size from 5612 bp to 15142 bp for recA
+ and from 5428 bp to 13289 for recA
− cells. Three deletions from recA
+ cells and five deletions from recA
− cells were found to have occurred between short sequence repeats at the termini of the deletion, leaving one copy of the
repeat in the mutant sequence. Seven deletions from recA
+ cells and three deletions from recA
− cells did not have repeats at their termini; in these cases, the DNA sequences that are adjacent to the deletion termini
in the wild-type are characterized by short (2–4 bp) repeats. From these results, a model is presented for the generation
of deletion mutations which involves formation of an asymmetric crossover mediated by repeated sequences of 2- to 4-bp.
Received: 14 September 1998 / Accepted: 22 December 1998 相似文献
7.
8.
Alasdair J. E. Gordon Jennifer A. Halliday Michael J. Horsfall Barry W. Glickman 《Molecular & general genetics : MGG》1991,227(1):160-164
Summary A novel forward mutational system, based on the acquisition of an Iq-d dominant phenotype from an initial Iq− recessive state, was used to identify second-site frameshift mutation [±1(±3
n
) events] within the N-terminal region of thelacI gene ofEscherichia coli. The DNA sequences are described of forty-six spontaneous and twenty 9-aminoacridine(9-AA)-induced second site mutations.
Although −1 frameshift events dominate both spectra, the nature and site specificity of these events clearly distinguish two
mutational distributions. The spontaneous distribution contains two −(A: T) frameshift hotspots; one within a monotonic A5 run (9 occurrences), the other at a 5′-CACAACAAC-3′ sequence (12 occurrences). In contrast 17 of the 20 mutations recovered after 9-AA treatment involve the loss of a
G: C pair, 14 of which occur at a single site (5′-CGGGC-3′). The striking specificity of the observed mutational hotspots is of interest since this open genetic target contains
similar sequences which were infrequently recovered. 相似文献
9.
Kemal?O. Yariz Duygu Duman Celia?Zazo Seco Julia Dallman Mingqian Huang Theo?A. Peters Asli Sirmaci Na Lu Margit Schraders Isaac Skromne Jaap Oostrik Oscar Diaz-Horta Juan?I. Young Suna Tokgoz-Yilmaz Ozlem Konukseven Hashem Shahin Lisette Hetterschijt Moien Kanaan Anne?M.M. Oonk Yvonne?J.K. Edwards Huawei Li Semra Atalay Susan Blanton Alexandra?A. DeSmidt Xue-Zhong Liu Ronald?J.E. Pennings Zhongmin Lu Zheng-Yi Chen Hannie Kremer Mustafa Tekin 《American journal of human genetics》2012,91(5):872-882
10.
Primary production of phytoplankton and secondary production of a daphnid and a chaoborid were studied in a small eutrophic
pond. The gross primary production of phytoplankton was 290 gC m−2 per 9 months during April–December. Regression analysis showed that the gross primary production was related to the incident
solar radiation and the chlorophylla concentration and not to either total phosphorus or total inorganic nitrogen concentration. The mean chlorophylla concentration (14.2 mg m−3), however, was about half the expected value upon phosphorus loading of this pond. The mean zooplankton biomass was 1.60
g dry weight m−2, of whichDaphnia rosea and cyclopoid copepods amounted to 0.69 g dry weight m−2 and 0.61 g dry weight m−2, respectively. The production ofD. rosea was high during May–July and October and the level for the whole 9 months was 22.6 g dry weight m−2.Chaoborus flavicans produced 10 complete and one incomplete cohorts per year. Two consecutive cohorts overlapped during the growing season. The
maximum density, the mean biomass, and the production were 19,100 m−2, 0.81 g dry weight m−2, and 11.7 g dry weight m−2yr−1, respectively. As no fish was present in this pond, the emerging biomass amounted to 69% of larval production. The production
ofC. flavicans larvae was high in comparison with zooplankton production during August–September, when the larvae possibly fed not only
on zooplankton but also algae. 相似文献
11.
J. Casqueiro O. Ba?uelos S. Gutiérrez M. J. Hijarrubia J. F. Martín 《Molecular & general genetics : MGG》1999,261(6):994-1000
Recombination between direct repeats has been studied in Penicillium chrysogenum using strain TD7-88 (lys− pyr+), which contains two inactive copies of the lys2 gene separated by 4.5 kb of DNA (including the pyrG gene) in its genome. Gene conversion leading to products with the lys+ pyr+ phenotype was observed at a frequency of 1 in 3.2 × 103 viable spores. Two types of deletion events giving rise to lys+ pyr− and lys− pyr− phenotypes were obtained with different frequencies. Southern analysis revealed that gene conversion occurs mainly as a result
of crossing over events that remove the BamHI frameshift mutation present in one of the repeats. In lys− pyr− recombinants, the deletion events do not affect the frameshift mutation in the BamHI site, while lys+ pyr− recombinants showed repair of the BamHI frameshift mutation and the genotype of the parental non-disrupted strain was restored. In summary, deletion events in
P. chrysogenum tend to favor the restoration of the phenotype and genotype characteristic of the parental non-disrupted strain.
Received: 9 November 1998 / Accepted: 14 April 1999 相似文献
12.
Franciane Pellizzari Eurico C. Oliveira Nair S. Yokoya 《Journal of applied phycology》2008,20(1):75-82
Gayralia K.L. Vinogr. is a monostromatic green alga of commercial importance in the southern Brazil, and its cultivation is being
considered. This paper reports some basic aspects of the biology of this poorly known genus. Two populations of Gayralia spp., from outer and inner sectors of Paranaguá Bay, showed an asexual life history with a distinct pattern of thallus ontogeny.
In one population (Gayralia sp. 1), zooids developed an expanded monostromatic blade directly, while in the other (Gayralia sp. 2) zooids produced an intermediate saccate stage, before giving rise to a monostromatic blade. Thalli of the two species
differ in size and in cell diameter. The effects of temperature (16–30°C), irradiance (50–100 μmol photons m−2 s−1), and salinity (5–40 psu) on the growth of both populations were assessed. Plantlets of Gayralia sp. 1 from in vitro cultures showed a broader tolerance to all salinity and irradiance levels tested, with the highest growth
rate (GR; mean 17% day−1) at 21.5°C and 100 μmol photons m−2 s−1. Plantlets of Gayralia sp. 1 collected during the winter in the field showed higher GR, ranging from 5% day−1 to 7.5% day−1 in salinities from 20 to 40 psu, and 2.0% day−1 and 4.3% day−1 for plantlets collected during the summer. Gayralia sp. 2 from the field showed highest GR at salinity of 15 psu. These results suggest distinct physiological responses of the
two species, in accordance with their distribution: Gayralia sp. 2 is limited to the inner areas of the estuary, while Gayralia sp. 1 grows in outer areas, where salinity values are higher than 20 psu. These data indicate that Gayralia sp. 1 has a higher potential for aquaculture than Gayralia sp. 2 due to its larger thalli, higher GR, and wider tolerance to environmental variations. 相似文献
13.
The LCCL module. 总被引:9,自引:0,他引:9
Here we show that Lgl1 protein, cub-1-related proteins, coch-5b2-related proteins, coagulation factor C of horse-shoe crab and a predicted protein of Plasmodium falciparum share a homologous domain. Since this domain-type was first identified in Limulus factor C, Coch-5b2 and Lgl1 we propose the name LCCL for this domain-family. The LCCL module of coch-5b2 is of special biological interest because it has been shown recently that mutations affecting this module cause the deafness disorder DFNA9 in humans. With a view to defining the structure and function of the LCCL domain of human coch-5b2 protein, we have expressed it in Escherichia coli and subjected it to preliminary structural characterization. Structure prediction and circular dichroism studies on the recombinant protein indicate that the domain possesses both alpha helices and beta strands. It is shown that the mutations which cause hearing loss in humans affect residues that are critical for the integrity of the LCCL module of the coch-5b2 protein. 相似文献
14.
Raúl Muñoz María Hernández Ana Segura Joao Gouveia Antonia Rojas Juan Luis Ramos Santiago Villaverde 《Applied microbiology and biotechnology》2009,83(1):189-198
The long-term performance and stability of Pseudomonas putida mt-2 cultures, a toluene-sensitive strain harboring the genes responsible for toluene biodegradation in the archetypal plasmid
pWW0, was investigated in a chemostat bioreactor functioning under real case operating conditions. The process was operated
at a dilution rate of 0.1 h−1 under toluene loading rates of 259 ± 23 and 801 ± 78 g m−3 h−1 (inlet toluene concentrations of 3.5 and 10.9 g m−3, respectively). Despite the deleterious effects of toluene and its degradation intermediates, the phenotype of this sensitive
P. putida culture rapidly recovered from a 95% Tol− population at day 4 to approx. 100% Tol+ cells from day 13 onward, sustaining elimination capacities of 232 ± 10 g m−3 h−1 at 3.5 g Tol m−3 and 377 ± 13 g m−3 h−1 at 10.9 g Tol m−3, which were comparable to those achieved by highly tolerant strains such as P. putida DOT T1E and P. putida F1 under identical experimental conditions. Only one type of Tol− variant, harboring a TOL-like plasmid with a 38.5 kb deletion (containing the upper and meta operons for toluene biodegradation), was identified. 相似文献
15.
Paclitaxel and 10-deacetylbaccatin III (10-DAB III) were produced in suspension cultures of Taxus × media var. Hicksii grown in shake-flasks and in a 7-l bioreactor reaching, in the bioreactor, 4.4 mg l−1 (on day 14) and 37.5 mg l−1 (on day 11). In shake-flasks the highest total content of paclitaxel and 10-DAB III was 7.3 mg l−1 (on day 4) and 8.8 mg l−1 (on day 18). Phenylalanine, at 0.05 mM, increased paclitaxel accumulation in cells cultivated in bioreactor and flasks 30-fold and 9-fold (from 0.02 mg l−1 to 0.6 mg l−1 and to 0.2 mg l−1, respectively). The 10-DAB III content in cells from flasks was increased from 0.4 mg l−1 to 1.6 mg l−1. 相似文献
16.
Wenyan Wang Chenggang Wang Bang-Lian Huang Bangquan Huang 《Plant Cell, Tissue and Organ Culture》2008,92(2):165-171
A protocol was developed for regeneration and Agrobacterium-mediated genetic transformation of Lesquerella fendleri. Calli were first induced from hypocotyls and cotyledons on MS plus 0.5 mg l−1 BA, 1 mg l−1 NAA and 1 mg l−1 2,4-D, then co-cultivated for 2–3 days in darkness on MS supplemented with 0.5 mg l−1 BA, 0.2 mg l−1 NAA and 100 μmol l−1As together with Agrobacterium tumefaciens strain EHA105/pCAMBIA1301 that harbored genes for uidA (GUS) and hygromycin resistance. Following co-cultivation, calli transfected by A. tumefaciens were transferred to MS with 0.5 mg l−1 BA, 0.2 mg l−1NAA, 500 mg l−1 Cef and 10 mg l−1 hygromycin and cultured for 10 days, then the hygromycin was increased to 20 mg l−1 on the same medium. After 4 weeks the resistant regenerants were transferred to MS with 0.5 mg l−1BA, 0.2 mg l−1 NAA, 500 mg l−1 Cef and 25 mg l−1 hygromycin for further selections. Transgenic plants were confirmed by polymerase chain reaction analysis, GUS histochemical
assay and genomic Southern blot hybridization. With this approach, the average regeneration frequency from transfected calli
was 22.70%, and the number of regenerated shoots per callus was 6–13. Overall results described in this study demonstrate
that Agrobacterium-mediated transformation is a promising approach for improvement of this Lesquerella species. 相似文献
17.
F. Andrieux-Loyer X. Philippon G. Bally R. Kérouel A. Youenou J. Le Grand 《Biogeochemistry》2008,88(3):213-231
The macrotidal estuary of Penzé (Brittany, Western part of the Channel, France) has been subjected to recurrent annual toxic
blooms of Alexandrium minutum since 1988. This study aims to specify the phosphorus dynamics and bioavailability in sediments in order to improve our understanding
of Alexandrium occurrences. Sediment-P pools and diffusive phosphate fluxes were studied under similar hydrodynamic conditions, in the intermediate
estuary in May, June and July 2003 and along the salinity gradient from August 2004 to June 2005. The results highlight a
decrease in bioavailable phosphorus (iron and organic bound) from the inner part of the estuary seaward. The ratio of iron-bound
phosphorus to iron-oxyhydroxides is lower in the inner and intermediate estuaries (5–8) than in the outer site (15), suggesting
a saturation of sorption sites and greater phosphorus bioavailability in this area. Pools of bioavailable phosphorus in surficial
sediments are about eight times higher than the annual net-export of P (7 ton year−1). Phosphate releases from sediments are always lower than 5 μmol m−2 d−1 in March. The highest supplies occur in June and August in the intermediate area (up to 400 μmol m−2 d−1) where they represent up to 50% of river loadings. These results further suggest that phosphate pulses coincide with occurrences
of Alexandrium reported in June. 相似文献
18.
In yeast, Arc1p interacts with ScMetRS and ScGluRS and operates as a tRNA-Interacting Factor (tIF) in trans of these two synthetases. Its N-terminal domain (N-Arc1p) binds the two synthetases and its C-terminal domain is an EMAPII-like
domain organized around an OB-fold-based tIF. ARC1 is not an essential gene but its deletion (arc1
− cells) is accompanied by a growth retardation phenotype. Here, we show that expression of N-Arc1p or of C-Arc1p alone palliates
the growth defect of arc1
− cells, and that bacterial Trbp111 or human p43, two proteins containing EMAPII-like domains, also improve the growth of an
arc1
− strain. The synthetic lethality of an arc1
−
los1
− strain can be complemented with either ARC1 or LOS1. Expression of N-Arc1p or C-Arc1p alone does not complement an arc1
−
los1
− phenotype, but coexpression of the two domains does. Our data demonstrate that Trbp111 or p43 may replace C-Arc1p to complement
an arc1
−
los1
− strain. The two functional domains of Arc1p (N-Arc1p and C-Arc1p) are required to get rid of the synthetic lethal phenotype
but do not need to be physically linked. To get some clues to the discrete functions of N-Arc1p and C-Arc1p, we targeted ScMetRS or tIF domains to the nuclear compartment and analyzed their cellular localization by using GFP fusions, and their ability
to sustain growth. Our results are consistent with a model according to which Arc1p is a bifunctional protein involved in
the subcellular localization of ScMetRS and ScGluRS via its N-terminal domain and of tRNA via its C-terminal domain. 相似文献
19.
Sherri M. Jones Timothy A. Jones Roshni Shukla 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(6):631-638
Short-latency vestibular-evoked potentials to pulsed linear acceleration were characterized in the quail. Responses occurred
within 8 ms following the onset of stimuli and were composed of a series of positive and negative peaks. The latencies and
amplitudes of the first four peaks were quantitatively characterized. Mean latencies at 1.0 g ms−1 ranged from 1265 ± 208 μs (P1, N = 18) to 4802 ± 441 μs (N4, N = 13). Amplitudes ranged from 3.72 ± 1.51 μV (P1/N1, N = 18) to 1.49 ± 0.77 μV (P3/N3, N = 16). Latency-intensity (LI) slopes ranged from −38.7 ± 7.3 μs dB−1 (P1, N = 18) to −71.6 ± 21.9 μs dB−1 (N3, N = 15) and amplitude-intensity (AI) slopes ranged from 0.20 ± 0.08 μV dB−1 (P1/N1, N = 18) to 0.07 ± 0.04 μV dB−1 (P3/N3, N = 11). The mean response threshold across all animals was −21.83 ± 3.34 dB re: 1.0 g ms−1 (N = 18). Responses remained after cochlear extirpation showing that they could not depend critically on cochlear activity.
Responses were eliminated by destruction of the vestibular end organs, thus showing that responses depended critically and
specifically on the vestibular system. The results demonstrate that the responses are vestibular and the findings provide
a scientific basis for using vestibular responses to evaluate vestibular function through ontogeny and senescence in the quail.
Accepted: 18 January 1997 相似文献
20.
An endophytic Xylaria sp., having broad antimicrobial activity, was isolated and characterized from Ginkgo biloba L. From the culture extracts of this fungus, a bioactive compound P3 was isolated by bioactivity-guided fractionation and
identified as 7-amino-4-methylcoumarin by nuclear magnetic resonance, infrared, and mass spectrometry spectral data. The compound
showed strong antibacterial and antifungal activities in vitro against Staphylococcus aureus [minimal inhibitory concentrations (MIC) 16 μg·ml−1], Escherichia coli (MIC, 10 μg·ml−1), Salmonella typhia (MIC, 20 μg·ml−1), Salmonella typhimurium (MIC, 15 μg·ml−1), Salmonella enteritidis (MIC, 8.5 μg·ml−1), Aeromonas hydrophila (MIC, 4 μg·ml−1), Yersinia sp. (MIC, 12.5 μg·ml−1), Vibrio anguillarum (MIC, 25 μg·ml−1), Shigella sp. (MIC, 6.3 μg·ml−1), Vibrio parahaemolyticus (MIC, 12.5 μg·ml−1), Candida albicans (MIC, 15 μg·ml−1), Penicillium expansum (MIC, 40 μg·ml−1), and Aspergillus niger (MIC, 25 μg·ml−1). This is the first report of 7-amino-4-methylcoumarin in fungus and of the antimicrobial activity of this metabolite. The
obtained results provide promising baseline information for the potential use of this unusual endophytic fungus and its components
in the control of food spoilage and food-borne diseases. 相似文献