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At least 19 recordsLinked to original sources

PubMed1983

Association between the degree of mosaicism and the severity of syndrome in Turner mosaics and Klinefelter mosaics.

This study, based on the investigations carried on 82 cases of Turners of which 50 of them were mosaics and 85 cases of Klinefelters of which 70 of them were mosaics, is an attempt to explain the vast range of clinical variations observed in cytogenetically established Turner mosaics (45,X/46,XX) and Klinefelter mosaics (47,XXY/46,XY) in the light of the degree of mosaicism present in them. It was observed that the severity of the syndrome in Turner mosaics and Klinefelter mosaics increased with the relative increase in the abnormal cell line population.

Adult↗

PubMed2002

Effects of barley yellow mosaic disease resistant gene rym1 on the infection by strains of Barley yellow mosaic virus and Barley mild mosaic virus.

Although a Chinese landrace of barley, Mokusekko 3, is completely resistant to all strains of Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV), and is known to have at least two resistant genes, rym1 and rym5, only rym5 has been utilized for BaYMV resistant barley breeding in Japan. In order to clarify the effect of rym1 on BaYMV and BaMMV, and to utilize the gene for resistant barley breeding, the susceptibilities of only rym1 carrying breeding lines against BaYMV and BaMMV were investigated. In the assessment of resistance to BaYMV-I, 341 F(2) populations derived from a cross between the resistant line Y4 with only rym1 and the susceptible cv Haruna Nijo shows that the segregation loosely fits a 1R:3S ratio (0.05 > P > 0.01), suggesting that the resistance is controlled by a single recessive gene, rym1. Further, none of the F(3) lines derived from the nine resistant F(2) plants showed any disease symptoms in the field infected by BaYMV-I. The same nine F(3) lines showed almost the same agronomic characters in the field infected by BaYMV-III as those in the uninfected field, apart from the symptom of showing numerous mosaics. This result indicates that the gene rym1 has an acceptable level of resistance to BaYMV-III. In the assessment of resistance to BaYMV-II, BaMMV-Ka1 and -Na1, an artificial infection method was adopted and the susceptibilities to those viruses were investigated. Although the control varieties, Ko A and Haruna Nijo, were infected with all of them, the rym1 gene carrying BC(2)F(3) lines were completely resistant to all strains. In summary, rym1 is completely resistant to BaYMV-I, -II, BaMMV-Ka1 and -Na1, and has an acceptable level of resistance to BaYMV-III. This study concludes with a discussion of the reason why the important resistance gene rym1 was eliminated along with resistant cultivars during breeding for resistance to BaYMV.

Genes, Plant↗

PubMed2000

In vitro transcription by the turnip yellow mosaic virus RNA polymerase: a comparison with the alfalfa mosaic virus and brome mosaic virus replicases.

Recently, we showed that the main determinant in the tRNA-like structure of turnip yellow mosaic virus RNA to initiate minus-strand synthesis in vitro is the 3' ACCA end. By mutational analysis of the 3'-terminal hairpin, we show here that only a non-base-paired ACCA end is functional and that the stability of the wild-type 3'-proximal hairpin is the most favorable, in that it has the lowest DeltaG value and a high transcription efficiency. With a nested set of RNA fragments, we show that the minimum template length is 9 nucleotides and that transcription is improved with increasing the length of the template. The results also suggest that proper base stacking contributes to efficient transcription initiation. Internal initiation is shown to take place on every NPyCPu sequence of a nonstructured template. However, the position of the internal initiation site in the template is important, and competition between the different sites takes place. Internal initiation was also studied with the RNA-dependent RNA polymerase of brome mosaic virus (BMV) and alfalfa mosaic virus (AlMV). The BMV polymerase can start internally on ACCA sequences, though inefficiently. Unexpectedly, the polymerases of both AlMV and BMV can start efficiently on an internal AUGC sequence.

Alfalfa mosaic virus↗

PubMed1994

The occurrence of mixed infections of turnip mosaic, cauliflower mosaic and cucumber mosaic viruses in winter oilseed rape from the territory of Uzbekhistan.

Turnip mosaic, cauliflower mosaic and cucumber mosaic viruses (TuMV, CaMV and CMV) were isolated and identified from winter oilseed rape plants from Uzbekhistan. This is the first record on the occurrence of CaMV and of mixed infection of rape with the three aforementioned viruses from the territory of the former Soviet Union.

Mosaic Viruses↗

PubMed1997

European collaborative research on mosaicism in CVS (EUCROMIC)--fetal and extrafetal cell lineages in 192 gestations with CVS mosaicism involving single autosomal trisomy.

Cytogenetic information on cells from cytotrophoblast, villus mesenchyme, and one or more fetal tissues was available for 192 gestations with mosaicism or non-mosaic fetoplacental discrepancy involving a single autosomal trisomy in the chorionic villus sample (CVS), registered in a collaborative study (EUCROMIC) during the period 1986-1994. In order to identify predictors of confined placental mosaicism (CPM), generalized mosaicism and/or uniparental disomy (UPD), distribution of the mosaic and nonmosaic aneuploid cell lines in the different fetal and extrafetal cell lineages were analyzed. Data were related to existing hypotheses on mechanisms leading to fetoplacental discrepancies and early extraembryonic cell differentiation. Trisomy 21 mosaicism was the one most frequently confirmed in the fetus. Non-mosaic trisomy 13, 18, and 21 in the villus mesenchyme indicated the presence of a trisomic cell line in the fetus proper. Non-mosaic trisomy 2, 7, and 16 in villus mesenchyme was always found with concomitant mosaic or non-mosaic trisomy in the cytotrophoblast, but was never recovered in the fetus. Mosaic trisomy 3, 7, and 20 was predominantly restricted to the cytotrophoblast, mosaic trisomy 2 to the villus mesenchyme. Trisomies 15 and 16 were most often found in both cytotrophoblast and villus mesenchyme and not in fetal cells. This supports the hypothesis that mosaicism/discrepancy for trisomies 15 and 16 results more often than for the other trisomies from trisomic zygote rescue, enhancing their risk for UPD. We recommend, due to the risk of fetal trisomy, amniocentesis in all gestations involving mosaic autosomal trisomy in villus mesenchyme. In gestations with mosaic or non-mosaic autosomal trisomy in both cytotrophoblast and villus mesenchyme we recommend, in order to exclude fetal trisomy and/or UPD, depending on the chromosome involved, further examination by amniocentesis, ultrasound and/or test for UPD. We also recommend, due to a small but not negligible risk of false negative and false positive diagnoses, not to solely use direct preparation.

Cell Lineage↗

PubMed1996

Risk of fetal mosaicism when placental mosaicism is diagnosed by chorionic villus sampling.

OBJECTIVE: Our purpose was to determine the risk of fetal mosaicism when placental mosaicism is found on chorionic villus sampling. STUDY DESIGN: We present a case of mosaic trisomy 22 detected on chorionic villus sampling and subsequently found in the fetus. A review of comprehensive chorionic villus sampling studies with emphasis on follow-up for fetal mosaicism was conducted. RESULTS: Among 13 studies reviewed, 469 cases of placental mosaicism are presented; fetal mosaicism was found in 50 (10.7%). Factors associated with fetal mosaicism are (1) mosaicism on mesenchymal core culture and (2) type of chromosome abnormality involved--specifically, marker chromosomes (26.7%) and common autosomal trisomies (19.0%). Amniocentesis predicted fetal genotype in 93% to 100% of cases of placental mosaicism, depending on the cell type in which mosaicism was diagnosed. CONCLUSIONS: Although mosaicism is usually confined to the placenta, the fetus is involved in about 10% cases. Patients should be counseled about this risk and the accuracy of follow-up amniocentesis.

Adult↗

PubMed1997

Accuracy of cytogenetic findings on chorionic villus sampling (CVS)--diagnostic consequences of CVS mosaicism and non-mosaic discrepancy in centres contributing to EUCROMIC 1986-1992.

Of 62,865 karyotyped chorionic villus (CV) samples that were reported to EUCROMIC 1986-1992, 98.5 per cent showed either a normal karyotype (true negative result; 94.8 per cent of the total) or a non-mosaic chromosomal aberration (true positive non-mosaic result; 3.7 per cent). True fetal mosaicism was diagnosed in about 0.15 per cent of the 62,865 CV samples, while confined placental mosaicism (CPM) occurred in 1.0 per cent. False-positive non-mosaic aberrations were observed in 0.15 per cent and false-negative CVS (chorionic villus sampling) results in only 0.03 per cent. The remaining 0.15 per cent of the CVS results were unclassifiable. These figures determined a sensitivity of CVS for prenatal detection of chromosome aberrations of 98.9-99.6 per cent (95 per cent confidence intervals), a specificity of 98.5-98.8 per cent, a positive predictive value of 72.6-78.3 per cent, and a negative predictive value of 99.95-99.98 per cent. False-positive non-mosaic aberrations that could not from the outset be suspected of being confined to the placenta were very rare (0.07 per cent of CV samples). They most often involved non-mosaic monosomy X and trisomy 18 encountered after direct preparation alone. False-negative CVS results were extremely rare (0.03 per cent) and occurred, with only one exception, after direct preparation alone. Thirteen of the 19 false-negative CVS diagnoses were from pregnancies at a particularly high risk for fetal chromosomal aberration. Seventy-five per cent of the pregnancies with CVS mosaicism or non-mosaic discrepancy and known outcome continued to livebirth. When CVS mosaicism was encountered, the definitive prenatal cytogenetic diagnosis was most often obtained through subsequent amniocentesis. However, the use of amniocentesis and the frequency of pregnancy termination depended on the type of chromosomal aberration involved. We conclude that CVS is an accurate method for prenatal chromosome analysis. In pregnancies at high risk for fetal chromosomal abnormality, we recommend, however, not relying solely on a normal karyotype obtained after direct preparation alone.

Abortion, Induced↗

PubMed2004

Issues arising from the prenatal diagnosis of some rare trisomy mosaics--the importance of cryptic fetal mosaicism.

OBJECTIVES: To add to the knowledge of fetal mosaicism, confined placental mosaicism (CPM), and uniparental disomy (UPD), in rare trisomies detected at prenatal diagnosis. METHODS: The origin of rare trisomy mosaics, mostly (8/11) seen in amniocytes, was examined in 11 cases by follow-up karyotyping and the study of microsatellite inheritance. RESULTS: Of the rare trisomies presented, three were mosaic trisomy 16 (two of which were CPM), and the remainder comprised single cases of mosaic trisomies of 8, 9, 10, 11, 12, 14, 5 and 15--the last two being CPM. Cases varied in parental derivation and meiotic versus post-zygotic origin but no case involved UPD. There was evidence for cryptic fetal mosaicism in three cases (5, 7, 11)--involving chromosomes 11, 14 and 16. CONCLUSIONS: These cases contribute further data to phenotypes associated with rare trisomies and the relative influences on the phenotype of CPM, UPD and fetal mosaicism. From sparse published data, we estimate that approximately 10% of apparent CPM cases for a rare trisomy (i.e. aneuploid CVS, normal amniocytes) may actually be cryptic fetal mosaics undetected in cultured amniocytes. In many cases, this cryptic mosaicism may be of limited clinical significance, but in others, the associated phenotypic effects may be obvious. There is no general approach to resolve this issue; the finding of even a few similar aneuploid cells in different amniocyte culture vessels may be clinically significant. It may be useful to study such an amniocyte culture with FISH with the relevant centromeric probe. Careful follow-up is recommended, particularly for infants where apparent correction of autosomal trisomy has occurred.

Adult↗

PubMed1992

Proposed guidelines for diagnosis of chromosome mosaicism in amniocytes based on data derived from chromosome mosaicism and pseudomosaicism studies.

Currently, accepted protocol which has been developed at the Prenatal Diagnosis Laboratory of New York City (PDL) requires that when a chromosome abnormality is found in one or more cells in one flask, another 20-40 cells must be examined from one or two additional flasks. Chromosome mosaicism is diagnosed only when an identical abnormality is detected in cells from two or more flasks. In a recent PDL series of 12,000 cases studied according to this protocol, we diagnosed 801 cases (6.68 per cent) of single-cell pseudomosaicism (SCPM), 126 cases (1.05 per cent) of multiple-cell pseudomosaicism (MCPM), and 24 cases (0.2 per cent) of true mosaicism. Pseudomosaicism (PM) involving a structural abnormality was a frequent finding (2/3 of SCPM and 3/5 of MCPM), with an unbalanced structural abnormality in 55 per cent of SCPM and 24 per cent of MCPM. We also reviewed all true mosaic cases (a total of 50) diagnosed in the first 22,000 PDL cases. Of these 50 cases, 23 were sex chromosome mosaics and 27 had autosomal mosaicism; 48 cases had numerical abnormalities and two had structural abnormalities. Twenty-five cases of mosaicism were diagnosed in the first 20 cells from two flasks, i.e., without additional work-up, whereas the other 25 cases required extensive work-up to establish a diagnosis (12 needed additional cell counts from the initial two culture flasks; 13 required harvesting a third flask for cell analysis). Our data plus review of other available data led us to conclude that rigorous efforts to diagnose true mosaicism have little impact in many instances, and therefore are not cost-effective. On the basis of all available data, a work-up for potential mosaicism involving a sex chromosome aneuploidy or structural abnormality should have less priority than a work-up for a common viable autosomal trisomy. We recommend revised guidelines for dealing with (1) a numerical versus a structural abnormality and (2) an autosomal versus a sex chromosome numerical aneuploidy. Emphasis should be placed on autosomes known to be associated with phenotypic abnormalities. These new guidelines, which cover both flask and in situ methods, should result in more effective prenatal cytogenetic diagnosis and reduced patient anxiety.

Amniocentesis↗

PubMed2005

[Trisomy 20 mosaicism revealed by pigmentary mosaicism of the Ito-type].

INTRODUCTION: Ito hypomelanosis-type pigmentary mosaicism is characterized by congenital pigmentation disorders along Blaschko's lines. We report a case of Ito-type pigmentary mosaicism associated with a congenital growth hormone deficiency having revealed trisomy 20 mosaicism. OBSERVATION: A 4 year-old boy presented with congenital pigmentation disorders. His history was marked by: inter-uterine delayed growth of unknown etiology, a dysmorphic syndrome, psychomotor retardation with speech problems, right cryptorchidia and an isolated, idiopathic, congenital growth hormone deficiency that had been treated with recombinant somatropine since the age of three. The clinical examination revealed alternating hypo and hyper-pigmented maculae with linear distribution on the limbs and in "twirls" on the trunk following Blaschko's lines. The blood karyotype was normal, the karyotype on fibroblasts of hypopigmented skin revealed trisomy 20 mosaicism. DISCUSSION: The occurrence of pigmentary mosaicism related to trisomy 20 mosaicism is exceptional. The combination of Ito hypomelanosis-type pigmentary mosaicism and delayed growth due to growth hormone deficiency has never been reported before. Our observation, unusual because of such an association, raises the question of the eventual existence of associated genes located on the chromosome 20 implied in the secretion of growth hormone and/or melanogenesis. It also underlines the interest of conducting cytogenic explorations on fibroblasts of damaged skin in the case of Ito-type pigmentary mosaicism, even if the blood karyotype is normal or in the absence of a patent phenotype abnormality.

Abnormalities, Multiple↗

PubMed2001

Tandem duplication mosaicism: characterization of a mosaic dup(5q) and review.

Mosaicism for tandem duplications is rare. Most patients reported had abnormal phenotypes of varying severity, depending on the chromosomal imbalance involved and the level of mosaicism. Post-zygotic unequal sister-chromatid exchange has been proposed as the main mechanism for tandem duplication mosaicism. However, previous molecular analyses have implicated both meiotic and post-zygotic origins for the duplication. We describe a newborn male who was originally diagnosed in utero with arrhythmia and tetralogy of Fallot. He had multiple dysmorphic features including telecanthus, blepharophimosis, high broad nasal bridge with a square-shaped nose, flat philtrum, thin upper lip, down-turned corners of the mouth, high-arched palate, micrognathia, asymmetric ears, and long, thin fingers and toes. Karyotyping of peripheral blood lymphocytes showed mosaicism for a tandem duplication of part of the long arm of one chromosome 5: mos46,XY,dup(5)(q13q33)[6]/46,XY[45]. Fibroblast cultures had the same mosaic karyotype with a higher frequency of the dup(5) clone: mos46,XY,dup(5)(q13q33)[9]/46,XY[21]. Fluorescence in situ hybridization analysis with a wcp5 confirmed the chromosome 5 origin of the additional material. Parental karyotypes were normal indicating a de novo origin of the dup(5) in the proband. Molecular analyses of chromosome 5 sequence-tagged-site (STS) markers in our family were consistent with a post-zygotic origin for the duplication. Therefore, mosaicism for tandem duplications can arise both through meiotic or mitotic errors, as a result of unequal crossing over or unequal sister-chromatid exchange, respectively. Our review indicates that mosaicism for tandem duplications is likely under-ascertained and that parental karyotyping of probands with non-mosaic tandem duplications should be performed.

Adult↗

PubMed2006

Confirmation of mosaicism and uniparental disomy in amniocytes, after detection of mosaic chromosome abnormalities in chorionic villi.

Chromosome mosaicism is detected in about 1-2% of chorionic villi samples (CVS), and may be due to a postzygotic nondisjunction event generating a trisomic cell line in an initially normal conceptus (mitotic origin) or the postzygotic loss of one chromosome in an initially trisomic conceptus (meiotic origin and trisomy rescue). Depending on the distribution of the abnormal cell line, the mosaic can be confined to the placenta (CPM) or generalised to the fetus (TFM, true fetal mosaicism). Trisomy rescue could theoretically be associated with a 33.3% probability of uniparental disomy (UPD) in the fetus. The aim of this study was to determine the risk of fetal involvement in a cohort of numerical and structural chromosome mosaics revealed in chorionic villi by means of combined direct and long-term culture analyses; we also determined the incidence of UPD associated with mosaic aneuploidies and supernumerary markers involving imprinted chromosomes. A total of 273 of a consecutive series of 15,109 CVS evaluated during a period of 5 years showed a mosaic condition in direct preparations and/or long-term cultures; confirmatory amniocentesis was performed in 203 cases. The abnormal cell line was extended to the fetus in 12.8% cases in terms of structural and numerical abnormalities involving autosomes and sex chromosomes; the risk of TFM varied and depended on the placental tissue distribution of the abnormal cell line. One of the 51 cases in which the mosaic involved an imprinted chromosome showed UPD, thus indicating a risk of 1.96%.

Amniotic Fluid↗

PubMed1998

Specific sequence changes in the 5'-terminal region of the genome of satellite tobacco mosaic virus are required for adaptation to tobacco mosaic virus.

The genome of satellite tobacco mosaic virus (STMV) adapted to tobacco mosaic virus (TMV), tomato mosaic virus or green tomato atypical mosaic virus consistently had two single base deletions at positions 1 and 61, corresponding to bases A and G, respectively, as compared to the type-strain genome which is naturally adapted to tobacco mild green mosaic virus (TMGMV). Transcript RNAs (STMV(TMV)) from clone pSTMV(TMV) which captured the deletions at positions 1 and 61 were infectious when co-inoculated to tobacco plants with either TMV or TMGMV at infection frequencies of > 90%. Two new STMV variants were created to investigate whether both deletions were essential for adaptation to TMV. These were STMV(TMGMV) deltaA1, which had the A at position 1 (A1) deleted, and STMV(TMGMV) deltaG61, which lacked G61. STMV(TMGMV) deltaA1 was infectious (75% frequency) in the presence of either TMV or TMGMV. Virion RNA of STMV(TMGMV) deltaA1 lost G61 after one infection cycle with TMV. This deletion did not occur in co-infections with TMGMV. STMV(TMGMV) deltaG61, like the clone STMV(TMGMV), was infectious (100% frequency) with TMGMV but TMV did not support this clone. When Nicotiana benthamiana protoplasts were transfected with STMV(TMGMV), STMV(TMGMV) deltaA1 or STMV(TMV), STMV replicated when TMGMV was the helper virus. STMV(TMV) and STMV(TMGMV) deltaA1 replicated in the presence of helper TMV, but STMV(TMGMV) did not, the same result as in whole plants. The deletion of A1 is thus essential for initial STMV adaptation to TMV and the eventual deletion of G61 is a predicted additional change.

Adaptation, Physiological↗

PubMed2002

Maize dwarf mosaic disease in different regions of China is caused by Sugarcane mosaic virus.

Sugarcane mosaic virus (SCMV) was detected in all 62 maize samples collected from eight maize-growing provinces in China showing dwarf mosaic symptoms by immunocapture reverse-transcription polymerase chain reaction (RT-PCR). Maize dwarf mosaic virus (MDMV), Sorghum mosaic virus (SrMV) and Johnsongrass mosaic virus (JGMV), however, were not detected in any of the samples by RT-PCR. Eleven cDNA fragments of approximately 0.8 kilobases covering most of the coat protein (CP) gene of SCMV were sequenced and sequence analysis indicates that these eleven isolates share 98.1 to 100 % identity at the amino acid level. Sequence comparison and phylogenetic analysis of the CP genes from the eleven Chinese isolates as well as 21 SCMV subgroup virus isolates indicate that the eleven Chinese virus isolates were closely related to SCMV with 97.0 to 98.1 % sequence identity at the amino acid level, while relatively lower sequence identity was found with MDWV, SrMV or JGMV. The results indicate that the Chinese isolates are members of the SCMV species, and thus, SCMV can be considered as the most common and important potyvirus infecting maize in China.

Amino Acid Sequence↗

PubMed2003

Meiotic segregation of sex chromosomes in mosaic and non-mosaic XYY males: case reports and review of the literature.

The aim of this study was to determine the incidence of sex chromosome aneuploidy in spermatozoa of two males with a 47,XYY karyotype and one male with a 46,XY/47,XYY constitution. Spermatozoa obtained from two oligospermic patients and one volunteer semen donor were studied by multicolour fluorescence in situ hybridization. In the XY/XYY male, the frequencies of X-bearing to Y-bearing sperm were significantly different from the 1 : 1 expected ratio. Significantly increased frequencies were found in the mosaic and non-mosaic males for 24,XX and 24,YY sperm when compared with control donors. The number of 24,XY sperm was significantly different from the controls in the XYY males, but not in the mosaic male. The incidence of disomy 18 and the rate of diploidy also increased in the three patients. However, the mosaic male had the lowest cumulative rate of disomic and diploid spermatozoa when compared with the two XYY patients. Our data suggest that: (i) chromosome abnormalities observed in spermatozoa of the two XYY oligoasthenoteratospermic (OAT) males arise through segregation errors in XY germ cells rather than normal meiosis of XYY germ cells, (ii) mosaic XYY males with normal semen parameters have a lower risk of producing offspring with a sex chromosomal abnormality than OAT males with XYY karyotype.

Adult↗

PubMed1990

Cucumber mosaic virus satellite RNA (Y strain): analysis of sequences which affect yellow mosaic symptoms on tobacco.

Plants infected with cucumber mosaic virus (CMV) (KIN strain) produce a mild mosaic disease on tobacco whereas infections of CMV with satellite RNA (strain Y) cause a severe yellow mosaic. Analysis of recombinant and mutant forms of satellite RNA identified a site (nucleotides 185/186) in the Y satellite RNA that affects the ability to induce the yellow mosaic in combination with CMV but not with tomato aspermy virus. The location of this site with respect to other mutations in the satellite RNA indicated that polypeptides, which may be encoded by the satellite RNA, have no role in induction of yellow mosaic symptoms. The symptom induction is therefore an effect of the satellite RNA on the host plant with the intervention of the helper virus. In the course of the mutation analysis of satellite RNA we detected several secondary mutations which arose in planta. Two of these were deletions of more than 80 nucleotides. Other forms of mutant satellite RNA were non-functional even though the modifications involved nucleotides completely within the large secondary deletions. These data imply complex intramolecular interactions in the satellite RNA.

Base Sequence↗

PubMed1987

[Mosaic tetrasomy 12p. Identical nature of the Pallister syndrome, the Teschler-Nicola/Killian syndrome and mosaic tetrasomy 21].

In two cases, first interpreted as mosaic tetrasomy 21, the R banding and the gene dosage studies lead us to conclude to a mosaic tetrasomy 12 p. In Pallister mosaic syndrome and in Teschler-Nicola/Killian syndrome, the very similar clinical signs and the identical abnormal chromosome, missing in leucocytes, led us to conclude that Pallister and Teschler-Nicola/Killian syndrome, as well as mosaic tetrasomy 21 are one and the same syndrome tetrasomy 12 p. This tissue limited mosaic is probably more frequent than it is assumed. Prenatal diagnosis can be made since the supernumerary chromosome is found in amniocytes. The distinctive tissue distribution is probably a selective process due to cellular differentiation gene, CD9 (or Alb 6) located to 12 p.

Aneuploidy↗

PubMed2005

Identification of a naturally occurring recombinant isolate of Sugarcane mosaic virus causing maize dwarf mosaic disease.

The complete nucleotide sequence of a potyvirus causing severe maize dwarf mosaic disease in Shaanxi province, northwestern China was determined (GenBank accession No. AY569692). The full genome is 9596 nucleotides in length excluding the 3 '-terminal poly (A) sequence. It contains a large open reading frame (ORF) flanked by a 149 nt 5'-untranslated region (UTR) and a 255 nt 3'-UTR. The putative polyprotein encoded by this large ORF comprises of 3063 amino acid residues. Sequence comparisons and phylogenetic analyses showed that this potyvirus is an isolate of Sugarcane mosaic virus (SCMV). The entire sequences shared identities of 89.6-97.6 % and 79.3-93.3% with 9 sequenced SCMV isolates at the nucleotide and deduced amino acid levels, respectively. But it showed much lower identities with Maize dwarf mosaic virus (MDMV), Sorghum mosaic virus (SrMV) and Johnsongrass mosaic virus (JGMV) isolates. The putative coat protein sequence is identical to that of a Chinese maize isolate SCMV-HZ. However, partition comparisons and phylogenetic profile analyses of the viral nucleotide sequences indicated that it is a recombinant isolate of SCMV. The recombination sites are located within the 6K1 and CI coding regions.

3' Untranslated Regions↗