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Basic Characteristics of Mutations
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Mutation Site
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A221V |
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Mutation Site Sentence
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Table 3. Genetic polymorphism in HTLV-1 tax |
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Mutation Level
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Amino acid level |
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Mutation Type
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Nonsynonymous substitution |
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Gene/Protein/Region
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tax |
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Standardized Encoding Gene
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tax
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Genotype/Subtype
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Transcontinental |
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Viral Reference
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J02029
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Functional Impact and Mechanisms
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Disease
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Paraparesis, Tropical Spastic
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Immune
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- |
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Target Gene
|
-
|
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Clinical and Epidemiological Correlations
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Clinical Information
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Y |
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Treatment
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- |
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Location
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- |
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Literature Information
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PMID
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34494950
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Title
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Polymorphisms in HTLV-1 Tax-responsive elements in HTLV-1-associated myelopathy/tropical spastic paraparesis patients are associated with reduced proviral load but not with disease progression
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Author
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Gomes YCP,Silva MTT,Leite ACCB,Lima MASD,Araujo AQC,Silva Filho IL,Vicente ACP,Espindola OM
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Journal
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The Journal of general virology
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Journal Info
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2021 Sep;102(9)
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Abstract
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Human T-lymphotropic virus type 1 (HTLV-1) provirus expression is mainly directed by Tax-responsive elements (TRE) within the long terminal repeats (LTR). Mutations in TRE can reduce provirus expression and since a high proviral load (PVL) is a risk factor for the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), we evaluated polymorphisms in the 5' LTR and the association with PVL and disease progression. HTLV-1 LTR and tax sequences derived from asymptomatic carriers (AC) and HAM/TSP patients followed in a longitudinal study were analysed according to PVL and clinical severity. Individuals infected with HTLV-1 presenting the canonical TRE, considering strain ATK-1 as the consensus, displayed sustained higher PVL. By contrast, an LTR A125G mutation in TRE was associated with slightly reduced PVL only in HAM/TSP patients, although it did not influence the speed of disease progression. Moreover, this polymorphism was frequent in Latin American strains of the HTLV-1 Cosmopolitan Transcontinental subtype. Therefore, polymorphisms in the 5' TRE of HTLV-1 may represent one of the factors influencing PVL in HAM/TSP patients, especially in the Latin American population. Indeed, higher PVL in the peripheral blood has been associated with an increased inflammatory activity in the spinal cord and to a poorer prognosis in HAM/TSP. However, this event was not associated with TRE polymorphisms.
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Sequence Data
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MK940595-MK940668; MF277043-MF277122
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