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1.
DNA polymorphisms in the ε- and γ-globin gene regions in nine Asian macaques(Macaca fuscata, M. mulatta, M. nemestrina, M. cyclopis, M. fascicularis, M. arctoides, M. radiata, M. maura, andM. assamensis) were examined using several different restriction endonucleases and the human ε and γIVS2 probes.M. fuscata andM. mulatta had highly polymorphic sites(BglII andHincII, respectively) in the ε-globin gene region. TheBamHI site in the γ-globin gene region was highly polymorphic inM. mulatta, while theBglII andHindIII sites in the γ-globin gene region were highly polymorphic inM. fuscata andM. mulatta. The presence of the γ-globin gene triplication was frequently observed inM. fuscata. The gain or loss of an additionalBglII site between two γ-globin genes in Asian macaques seems to be very meaningful for discussing genetic relationships among
them.
This study was supported in part by the Cooperation Research Program of the Primate Research Institute, Kyoto University. 相似文献
2.
3.
Sluan D. Lin Phil Cooper Jingly Fung Heinz-Ulrich G. Weier Edward M. Rubin 《Mammalian genome》2000,11(11):1024-1029
Genetic factors affecting postnatal γ-globin expression—a major modifier of the severity of both β-thalassemia and sickle
cell anemia—have been difficult to study. This is especially so in mice, an organism lacking a globin gene with an expression
pattern equivalent to that of human γ-globin. To model the human β-cluster in mice, with the goal of screening for loci affecting
human γ-globin expression in vivo, we introduced a human β-globin cluster YAC transgene into the genome of FVB/N mice. The
β-cluster contained a Greek hereditary persistence of fetal hemoglobin (HPFH) γ allele, resulting in postnatal expression
of human γ-globin in transgenic mice. The level of human γ-globin for various F1 hybrids derived from crosses between the FVB/N transgenics and other inbred mouse strains was assessed. The γ-globin level
of the (C3HeB/FeJ × FVB/N)F1 transgenic mice was noted to be significantly elevated. To map genes affecting postnatal γ-globin expression, we performed
a 20-centiMorgan (cM) genome scan of a (C3HeB/FeJ × FVB/N)F1 transgenics × FVB/N backcross, followed by high-resolution marker analysis of promising loci. From this analysis we mapped
a locus within an 18-cM interval of mouse Chromosome (Chr) 1 (LOD = 4.3) that contributes 10.9% of variation in γ-globin level.
Combining transgenic modeling of the human β-globin gene cluster with quantitative trait analysis, we have identified and
mapped a murine locus that impacts on human γ-globin level in vivo.
Received: 26 January, 2000 / Accepted: 2 May 2000 相似文献
4.
G. P. Patrinos Panagoula Kollia Aphrodite Loutradi-Anagnostou Dimitris Loukopoulos Manoussos N. Papadakis 《Human genetics》1998,102(6):629-634
We report a new type of non-deletional hereditary persistence of fetal hemoglobin that is due to a C→T transition at position
–158, relative to the Cap site of the human Aγ-globin gene. This mutation was identified in three unrelated adult cases presenting slightly elevated levels of fetal hemoglobin
(Hb F), i.e. 2.9–5.1%, and normal hematological indices. Our sequencing results, from both polymerase chain reaction-amplified
and subcloned DNA fragments, indicate that the Aγ–158C→T mutation occurred by two independent gene conversion events in the three cases studied. In addition, hematological
and molecular data, including restriction fragment length polymorphism haplotyping in the β-globin gene cluster, extended haplotype analysis inside the γ-globin gene region and routine analysis of three tandem repeat loci (D1S80, 3′-HVR/apoB and F8vWf), led us to conclude that
the Aγ–158C→T mutation in one of the three cases occurred recently in the parental germ line (P=99.47%), representing the first example of a de novo gene conversion event identified in humans.
Received: 10 November 1997 / Accepted: 10 February 1998 相似文献
5.
β-Thalassemia is the most common single gene disorder in Iran and more than 25,000 affected individuals have been reported.
It has been reported that in patients with β-thalassemia in the presence of Xmn1 polymorphic site the level of Hb F and Gγ: Aγ ratio is increased. The prevalence of Xmn1 polymorphic site, Gγ: Aγ ratio and Hb F in 197 β-thalassemia major patients from the Kermanshah Province of Iran were studied. The Xmn1 polymorphic site was determined by PCR-RFLP procedure. The levels of Gγ and Aγ chains were detected by HPLC. The percent of Hb F was determined using electrophoresis method. In β-thalassemia major patients
the frequency of presence Xmn1 was 0.39. The mean of Gγ: Aγ ratio was found to be 2.5. In the present study it was found that in the presence of Xmn1 polymorphic site Gγ percent and Gγ: Aγ ratio were significantly increased (P = 0.01) and the clinical features such as splenomegaly and bone marrow expansion were significantly improved (P = 0.01). We found that in the presence of Xmn1 polymorphic site on both chromosomes (+/+) the level of Hb F tended to be increased compared to the absence of Xmn1 (−/−). The present investigation has studied the frequency of Xmn1 polymorphic site in β-thalassemia major patients from Western Iran and has revealed that the presence of this polymorphic
site caused a positive influence on Hb F production and the Gγ percent which could improve the clinical symptoms of β-thalassemia patients. 相似文献
6.
Background
A potential strategy for treatment of sickle cell disease (SCD) and β-thalassemia in adults is reactivation of the ε- and γ-globin genes in the adult. We aimed to identify trans-activators of ε- and γ-globin expression and provide new candidate targets for effective treatment of sickle cell disease (SCD) and β-thalassemia through activation of ε- and γ-globin genes in adults. 相似文献7.
M. Bellucci A. Alpini F. Paolocci L. Cong S. Arcioni 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(5-6):796-804
Two gene constructs (pROK.TG1L and pROK.TG1LK) were utilized to achieve accumulation of maize γ-zein to high levels in tobacco
(Nicotiana tabacum L.) leaves. Both the chimaeric genes contained the γ-zein-coding region preceded by the 5′untranslated leader from the coat
protein mRNA of TMV, but one of them (pROK.TG1LK) was modified in its protein-coding region by the addition of the ER retention
signal KDEL. The accumulation of γ-zein and γ-zein:KDEL in leaves was compared with heterologous protein accumulation in tobacco
plants previously transformed with a γ-zein cDNA harbouring a native 5′UTR. Replacement of γ-zein 5′UTR with the TMV leader
dramatically increased γ-zein production. Furthermore, γ-zein:KDEL-expressing plants, on average, accumulated twice as much
foreign protein in their leaves as pROK.TG1L plants. The two-fold increase in the level of γ-zein:KDEL can probably be attributed
to an improvement in the mechanism for ER retention of zeins in the transgenic cells. Transformants also showed increased
production of BiP, though to a lesser extent in γ-zein:KDEL-expressing plants compared with pROK.TG1L plants. It is therefore
likely that γ-zein:KDEL retention is made less dependent on the chaperone assistance of BiP by the presence of the KDEL signal
on the γ-zein mutant.
Received: 15 October 1999 / Accepted: 28 February 2000 相似文献
8.
W. E. Rodriguez Romero M. Castillo M. A. Chaves G. F. Saenz L.-H. Gu J. B. Wilson E. Baysal N. S. Smetanina J. Y. Leonova T. H. J. Huisman 《Human genetics》1996,97(6):829-833
We have identified a minor hemoglobin component (∼5%) in the blood of a healthy Costa Rican female, but not in her mother
and two brothers (father not studied), that has an His→Arg replacement at position β77 (Hb Costa Rica). No other amino acid
replacements were observed and no β- or γ-chain-like peptides were present. Hb Costa Rica has a normal stability. Sequence
analyses of numerous polymerase chain reaction (PCR)-amplified segments of DNA that contain exon 2 of the β gene failed to
identify a CAC→CGC (His→Arg) mutation. The same was the case when cDNA was sequenced, indicating that a β-Costa Rica-mRNA could not be detected
with this procedure. Gene mapping of genomic DNA with BglII, BamHI, and HindIII gave normal fragments only and with the same intensity as observed for the fragments of a normal control. The quantities
of the β chain variants Hb J-Iran and Hb Fukuyama with related mutations at β77 vary between 30% and 45% in heterozygotes,
whereas that of Hb F-Kennestone with the same His→Arg mutation but in the Gγ-globin gene, is a high 40%–45% (as percentage of total Gγ) in a heterozygous newborn. These different observations exclude a heterozygosity of the A→G mutation at codon β77, as well
as a deletion comparable to that of Hbs Lepore or Kenya, or a β-globin gene duplication, and point to a nontraditional inheritance
of Hb Costa Rica. Allele-specific amplification of cDNA with appropriate primers identified the presence of a low level of
mutated mRNA in the reticulocytes of the patient, which was confirmed by dotblot analysis of the same material with 32P-labeled probes. Comparable amplification products were not observed in genomic DNA. The A→G mutation apparently occurred
in a somatic cell at a relatively early stage in the development of the hematopoietic cell system, and Hb Costa Rica accumulated
through rapid cell divisions in patchy areas in the bone marrow (somatic mosaicism). An unequal distribution of Hb Costa Rica
over the red cells supports this possibility.
Received: 25 August 1995 / Revised: 13 December 1995 相似文献
9.
Miki Watanabe Sulaiman Sheriff Theresa A. Ramelot Nijiati Kadeer Junho Cho Kenneth B. Lewis Ambikaipakan Balasubramaniam Michael A. Kennedy 《International journal of peptide research and therapeutics》2011,17(4):281-299
After severe burn injury, proinflammatory cytokine levels are elevated in serum and skeletal muscle, which in turn increases
protein breakdown and decreases protein synthesis. In this study, C2C12 mouse skeletal muscle cell line myotubes were exposed
to proinflammatory cytokines tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) as an in vitro cell-line model of catabolic
response to burn injury and then treated with des-acyl ghrelin (DAG), a 28 amino acid polypeptide hormone thought to inhibit
protein breakdown and increase protein synthesis, to assess its therapeutic potential. Nuclear magnetic resonance-based metabonomics
was used to monitor metabolic activity of C2C12 myotubes under four treatment conditions: (1) control, (2) TNF-α/IFN-γ (TI),
(3) DAG (DA), and (4) TNF-α/IFN-γ followed by DAG (TIDA) to assess the effect of DAG treatment on cellular metabolic response
during basal or catabolic conditions. Twelve metabolites showed significant changes in concentrations following treatments
in the hydrophilic cell extracts. Lactate (P < 10−4) and citrulline (P < 10−9) increased with TNF-α/IFN-γ treatment, indicating increased protein degradation, and returned to control levels in the TIDA
group. Adenosine nucleotide levels had decreased trends in TI myotubes that returned to baseline levels after DAG treatment
(P < 10−4). Guanidinoacetate and pantothenate, metabolites involved in protein synthesis and cell proliferation, had increased concentration
trends following DAG treatment in both the DA and TIDA groups. Our metabonomics analysis provides further evidence that DAG
counteracts the catabolic response caused by elevated muscle TNF-α/IFN-γ cytokine levels following severe burns and can play
a potential therapeutic role in treatment of burn injury. 相似文献
10.
Ariella Oppenheim Avi Yaari Deborah Rund Eliezer A. Rachmilewitz David Nathan Corinne Wong Haig H. Kazazian Jr. Barbara Miller 《Human genetics》1990,86(2):175-180
Summary The mechanism for elevated production of fetal hemoglobin (Hb F) in a Druze patient with °-thalassemia intermedia was investigated. Heterozygous family members exhibited normal Hb F levels, suggesting that the increase in -gene expression in the propositus may be partly due to anemic stress. Erythroid progenitors of these family members cultured in vitro [burst forming units (erythroid); (BFUe)] showed elevated synthesis of Hb F, indicating the existence of a genetically determined intrinsic capacity for high Hb F production in this family. The propositus was found to be homozygous for a IVS2-position 1 mutation, on the background of Mediterranean haplotype I, which is not known to be linked to high Hb F production. Moreover, extensive molecular studies of the -globin gene cluster, including sequence analysis of the promoter regions of the -globin genes, did not reveal any cisacting mechanism that could account for the high Hb F production in the propositus. A young niece of the propositus with °-thalassemia major was recently discovered, who was homozygous for the same -globin allele and haplotype as the propositus. However, unlike her uncle, she does not have a high Hb F level and presents with a severe clinical course. Her inability to produce high Hb F suggests that the genetic determinant for increased -gene expression in the propositus is unlinked to the -globin gene cluster. 相似文献
11.
In the present study we have examined whether p38 mitogen activated protein kinase (p38 MAPK) signal pathway interacts with
calcium signal on lipid accumulation in primary preadipocytes of mice. The primary preadipocytes were treated with p38 MAPK
inhibitor SB203580, blockers and excitomotors of calcium channel for 24 h, respectively. Intracellular triglyceride (TG) content
was measured by triglyceride kit and lipid accumulation was determined by Oil Red O staining. Meanwhile, the mRNA expressions
of peroxisome proliferators-activated receptor gamma (PPARγ) gene, fatty acid synthetase (FAS) gene, lipoprotein lipase (LPL) gene, vitamin D receptor (VDR) gene and extracellular Ca2+-sensing receptor (CaSR) gene were analyzed with real-time PCR. The protein content and phosphorylation of VDR and p38 were tested with Western Blotting.
The data showed that intracellular TG content and the mRNA expression levels of PPARγ, FAS, LPL in N group and L group as well as FAS, LPL in C group were increased significantly (P < 0.01) compared to the control. On the contrary, intracellular TG content and the mRNA expression levels of PPARγ, FAS in B group as well as intracellular TG content and PPARγ, FAS, LPL in SB group and B+SB group were decreased significantly (P < 0.01). VDR mRNA expression and protein content were decreased in B, C, and SB added groups (P < 0.01). In addition, p38 phosphorylation levels increased in N and L groups (P < 0.01) and decreased in SB added groups (P < 0.01). These findings suggest that p38 MAPK pathway through regulating VDR mRNA expression participates in mediation of calcium signal and affects calcium signal regulating lipid accumulation in mice
preadipocytes through changing PPARγ, FAS and LPL mRNA expression. In addition, calcium signal have a feedback effect in phosphorylation of p38. 相似文献
12.
Morita T Konishi M Fukuoka T Imura T Kitamoto D 《Applied microbiology and biotechnology》2006,73(2):305-313
The search for a novel producer of glycolipid biosurfactants, mannosylerythritol lipids (MEL) was undertaken based on the analysis of ribosomal DNA sequences on the yeast strains of the genus Pseudozyma. Pseudozyma rugulosa NBRC 10877 was found to produce a large amount of glycolipids from soybean oil. Fluorescence microscopic observation also demonstrated that the strain significantly accumulates polar lipids in the cells. The structure of the glycolipids produced by the strain was analyzed by 1H and 13C nuclear magnetic resonance and gas chromatography–mass spectrometry methods, and was determined to be the same as MEL produced by Pseudozyma antarctica, a well-known MEL producer. The major fatty acids of the present MEL consisted of C8 and C10 acids. Based on high performance liquid chromatography, the composition of the produced MEL was as follows: MEL-A (68%), MEL-B (12%), and MEL-C (20%). To enhance the production of MEL by the novel strain, factors affecting the production, such as carbon and nitrogen sources, were further examined. Soybean oil and sodium nitrate were the best carbon and nitrogen sources, respectively. The supplementation of a MEL precursor, such as erythritol, drastically enhanced the production yield from soybean oil at a rate of 70 to 90%. Under the optimal conditions in a shake culture, a maximum yield, productivity, and yield coefficient (on a weight basis to soybean oil supplied) of 142 g l−1, 5.0 g l−1 day−1, and 0.5 g g−1 were achieved by intermittent feeding of soybean oil and erythritol using the yeast. 相似文献
13.
Edrington TS Callaway TR Hallford DM Chen L Anderson RC Nisbet DJ 《Microbial ecology》2008,55(3):553-560
Fecal prevalence of Escherichia coli O157 in ruminants is highest in the summer decreasing to very low levels in the winter. We hypothesize that this seasonal
variation is a result of physiological responses within the host animal to changing day-length. To determine the effects of
melatonin (MEL) on fecal shedding of E. coli O157:H7 in cattle, eight crossbred beef steers identified as shedding E. coli O157:H7, were allotted to treatment: control or MEL (0.5 mg/kg body weight (BW); 1×) administered orally daily for 7 days.
After a 5-day period of no treatment, a second MEL dose (5.0 mg/kg BW; 10×) was administered daily for 4 days. Fecal samples
were collected daily for qualification of E. coli O157:H7. No differences (P > 0.10) were observed in the percentage of E. coli O157:H7 positive fecal samples in steers receiving the 1× MEL dose, however the 10× dose decreased (P = 0.05) the percentage of fecal samples E. coli O157:H7 positive. Serum MEL concentrations were higher in the 1×, but not 10×, treated animals compared to control animals.
Although it is difficult to explain, this may be a result of decreasing day-length increasing serum melatonin concentrations
that may have masked any treatment effect on serum melatonin. In a second similar experiment, a second group of cattle (heifers
and steers) were administered tryptophan (TRP) over a 17-day experimental period (5 g/head/day for 10 days followed by 10 g/head/day
for 7 days). Tryptophan had no effect (P > 0.20) on the percentage of fecal samples positive for E. coli O157. Serum TRP (P < 0.05), but not MEL (P > 0.20), concentrations were elevated in TRP-treated animals. The decrease in the number of positive fecal samples observed
in the first experiment, may be related to gastrointestinal MEL, affected by the 10×, but not 1× MEL dose. 相似文献
14.
Hadarits F Kisfali P Mohás M Maász A Duga B Janicsek I Wittmann I Melegh B 《Molecular biology reports》2012,39(2):1949-1955
The common functional variants of the apolipoprotein A5 (APOA5) and the glucokinase regulatory protein genes (GCKR) have been shown to associate with increased fasting triglyceride (TG) levels. Albeit the basic association has been extensively
investigated in several populations of different origin, less is known about quantitative traits of them. In our study accumulation
rates of four APOA5 (T-1131, IVS3 + G476A, T1259C and C56G) and two GCKR (C1337T and rs780094) functional SNPs were analyzed in patients stratified into four TG quartile groups. Randomly selected
325 metabolic syndrome patients were separated into four quartile (q) groups based on the TG levels as follows q1: TG <1.38 mmol/l;
q2: 1.38–1.93 mmol/l; q3: 1.94–2.83 mmol/l; and q4: TG >2.83 mmol/l. We observed significant stepwise increase of prevalence
rates of minor allele frequencies in the four plasma TG quartiles for three APOA5 SNPs: −1131C (q1: 4.94%; q2: 8.64%; q3: 11.6%; q4: 12.3%), IVS3 + 476A (q1: 4.32%; q2: 7.4%; q3: 10.36%; q4: 11.1%), and
1259C (q1: 4.94%; q2: 7.41%; q3: 10.4%; q4: 11.7%). The haplotype analysis revealed, that the frequency of APOA5*2 haplotype
gradually increased in q2, q3 and q4 (q1: 9.87%; q2: 14.8%; q3: 18.3%; q4: 21%). The distribution of the homozygotes of the
two analyzed GCKR variants resembled to the APOA5 pattern. Contrary to the hypothetically predictable linear association coming from the current knowledge about the APOA5 and GCKR functions, the findings presented here revealed a unique, TG raise dependent gradual accumulation of the functional variants
of in MS patients. Thus, the findings of the current study serve indirect evidence for the existence of rare APOA5 and GCKR haplotypes in metabolic syndrome patients with higher TG levels, which contribute to the complex lipid metabolism alteration
in this disease. 相似文献
15.
Hiroyuki Satoh Naomi Inokuchi Yasuhiro Nagae Taro Okazaki 《Journal of molecular evolution》1999,49(1):122-129
The β-globin gene cluster of Wistar rat was extensively cloned and the embryonic genes were mapped and sequenced. Four overlapping
λ Dash recombinant clones cover about 31 kb and contain four nonadult β-globin genes, 5′–ε1–γ1–γ2–ψγ3–3′. The ε1 and γ2 are
active genes, since their protein products were detected in the fetal stage of the rat (Iwahara et al., J Biochem 119:360–366,
1996). The γ1 locus might be a pseudogene, since the ATA box in the promoter region is mutated to GTA; however, no other defect
is observed. The ψγ3 locus is a truncated pseudogene because a 19-base deletion, which causes a shift of the reading frame,
is observed between the second nucleotide of the putative codon 68 and codon 76. A sequence comparison suggests that the ψγ3
might be produced by a gene conversion event of the proto-γ-globin gene set. Possible histories of the evolution of rat nonadult
β-globin genes are discussed.
Received: 6 August 1998 / Accepted: 12 February 1999 相似文献
16.
Fukuoka T Morita T Konishi M Imura T Sakai H Kitamoto D 《Applied microbiology and biotechnology》2007,76(4):801-810
Mannosylerythritol lipids (MELs), which are glycolipid biosurfactants produced by Pseudozyma yeasts, show not only excellent interfacial properties but also versatile biochemical actions. In the course of MEL production
from glucose as the sole carbon source, P. antarctica was found to produce unknown glycolipids more hydrophilic than conventional “di-acylated MELs,” which have two fatty acyl
esters on the mannose moiety. Based on a detailed characterization, the most hydrophilic one was identified as 4-O-(3′-O-alka(e)noyl-β-d-mannopyranosyl)-d-erythritol namely, “mono-acylated MEL.” The mono-acylated MEL reduced the surface tension of water to 33.8 mN/m at a critical
micelle concentration (CMC) of 3.6 × 10−4 M, and its hydrophilic–lipophilic balance was tentatively calculated to be 12.15. The observed CMC was 100-fold higher than
that of the MELs hitherto reported. Interestingly, of the yeast strains of the genus Pseudozyma, only P. antarctica and P. parantarctica gave the mono-acylated MEL from glucose, despite a great diversity of di-acylated MEL producers in the genus. These strains
produced MELs including the mono-acylated one at a rate of 20–25%. From these results, the new MEL is likely to have great
potential for use in oil-in-water-type emulsifiers and washing detergents because of its higher water solubility compared
to conventional MELs and will thus contribute to facilitating a broad range of applications for the environmentally advanced
surfactants. 相似文献
17.
A 191-kb genomic fragment containing the human α-globin locus can rescue α-thalassemic mice 总被引:1,自引:0,他引:1
Keith Al-Hasani Jim Vadolas Anja S. Knaupp Hady Wardan Lucille Voullaire Robert Williamson Panayiotis A. Ioannou 《Mammalian genome》2005,16(11):847-853
A 191-kb human bacterial artificial chromosome (BAC) containing the human α-globin genomic locus was used to generate transgenic
mice that express, exclusively, human α-globin (huα-globin). Expression of huα-globin reaches a level of 36% of that of endogenous mouse α-globin (muα-globin) on a heterozygous mouse α-thalassemia background (muα-globin knockout, muα+/−). Hemizygous transgenic mice carrying the huα-globin locus on a heterozygous knockout background (huα+/0, muα++/−−) demonstrated complementation of most hematologic parameters. By crossing huα+/0, muα++/−− mice, we were able to generate mice entirely dependent on huα-globin synthesis. Breeding and fluorescent in situ hybridization studies demonstrate that only mice homozygous for the transgene were able to rescue embryonic lethal homozygous
muα-globin knockout embryos (muα−−/−−). Adult rescued mice produce hemoglobin at levels similar to wild-type mice, with partial red cell complementation based
on mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and red cell distribution width (RDW) measurements. Significant
erythrocythemia above wild-type levels seems to be the main compensatory mechanism for the normalization of the hemoglobin
levels in the rescued animals. Our studies demonstrate that the huα-globin locus in the 191-kb transgene contains all the necessary elements for the regulated expression of huα-globin in transgenic mice. This animal model should be valuable for studying the mechanisms regulating huα-globin production and for development of therapeutic strategies for β-thalassemia based on downregulation of α-globin expression.
We dedicate this article to the memory of our valued friend and colleague Panayiotis A. Ioannou who passed away during the
completion of this work 相似文献
18.
Summary Repetitive DNA sequences, derived from the human β-globin gene cluster, were mapped within a series of human genomic DNA segments
containing core (H2A, H2B, H3 and H4) and H1 histone genes. Cloned recombinant λCH4A phage with human histone gene inserts
were analyzed by Southern blot analysis using the following32P-labeled (nick translated) repetitive sequences as probes:Alu I,Kpn I and LTR-like. A cloned DNA designated RS002-5′C6 containing (i)a (TG)16 simple repeat, (ii) an (ATTTT)n repeat and (iii)a 52 base pair alternating purine and pyrimidine sequence was also used as
a radiolabelled hybridization probe. Analysis of 12 recombinant phage, containing 6 arrangements of core histone genes, indicated
the presence ofAlu I,Kpn and RS002-5′C6 repetitive sequences. In contrast, analysis of 4 human genomic DNA segments, containing both core and H1 histone
genes, indicated the presence of onlyAlu I family sequences. LTR-like sequences were not detected in association with any of the core or H1 histone genes examined.
These results suggest that human histone and β-globin genes share certain aspects of sequence organization in flanking regions
despite marked differences in their overall structure and pattern of expression. 相似文献
19.
Yuanli Zhang Jiao Wang Xiaohui Zhang Jian-Qun Chen Dacheng Tian Sihai Yang 《Journal of molecular evolution》2009,68(4):393-402
Cultivated rice was domesticated from common wild rice. However, little is known about genetic adaptation under domestication.
We investigated the nucleotide variation of both cultivated rice and its wild progenitors at 22 R-gene and 10 non–R-gene loci. A significant regression was observed between wild rice and rice cultivars in their polymorphic levels, particularly
in their nonsynonymous substitutions (θ
a
). Our data also showed that a similar proportion (approximately 60%) of nucleotide variation in wild rice was retained in
cultivated rice in both R-genes and non–R-genes. Interestingly, the slope always was >1 and the intercept always >0 in linear regressions when a cultivar’s polymorphism
was x-axis. The slope and intercept values can provide a basis by which to estimate the founder effect and the strength of
artificial direct selection. A larger founder effect than previously reported and a strong direct-selection effect were shown
in rice genes. In addition, two-directional selection was commonly found in differentiated genes between indica and japonica rice subspecies. This kind of selection may explain the mosaic origins of indica and japonica rice subspecies. Furthermore, in most R-genes, no significant differentiation between cultivated and wild rice was detected. We found evidence for genetic introgression
from wild rice, which may have played an important role during the domestication of rice R-genes.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Yuanli Zhang and Jiao Wang contributed equally to this work. 相似文献
20.
A Ca2+-dependent TG activity, identified in the eye lens of several mammalian species, has long been implicated in cataract formation.
The precise mechanism of the involvement of this enzyme in this process remains unclear. The purpose of this work was to investigate
the modulatory effect of polyamines on TG activity during rabbit eye lens in vitro opacification. We observed, in an in vitro
Ca2+-induced cataract model, a rapid decrease of the endogenous levels of SPD with the progression of opacification, paralleled
by an increase of crystallin cross-linking by bis(γ-glutamyl)SPD. This pattern was reversed adding exogenous SPD to the incubation medium. Indeed, endogenous SPD levels were
restored and cross-linking by bis(γ-glutamyl)SPD were drastically reduced. Surprisingly, under this experimental condition, the loss of transparency of lens
was delayed. We found that exogenous SPD incubation led to a remarkable increase of mono(γ-glutamyl)SPD, likely responsible of the inhibition of cross-linking of lens crystallins and of the transparency persistence. 相似文献