Chromosomal distribution of the retroelements Rex 1, Rex 3 and Rex 6 in species of the genus Harttia and Hypostomus (Siluriformes: Loricariidae)

The transposable elements (TE) have been widely applied as physical chromosome markers. However, in Loricariidae there are few physical mapping analyses of these elements. Considering the importance of transposable elements for chromosomal evolution and genome organization, this study conducted the physical chromosome mapping of retroelements (RTEs) Rex1, Rex3 and Rex6 in seven species of the genus Harttia and four species of the genus Hypostomus, aiming to better understand the organization and dynamics of genomes of Loricariidae species. The results showed an intense accumulation of RTEs Rex1, Rex3 and Rex6 and dispersed distribution in heterochromatic and euchromatic regions in the genomes of the species studied here. The presence of retroelements in some chromosomal regions suggests their participation in various chromosomal rearrangements. In addition, the intense accumulation of three retroelements in all species of Harttia and Hypostomus, especially in euchromatic regions, can indicate the participation of these elements in the diversification and evolution of these species through the molecular domestication by genomes of hosts, with these sequences being a co-option for new functions.(AU)

Os elementos transponíveis (TE) têm sido amplamente aplicados como marcadores cromossômicos. Contudo, em Loricariidae, há poucas análises de mapeamento físico destes elementos. Considerando a importância de elementos transponíveis para a evolução cromossômica e organização genômica, este trabalho realizou o mapeamento físico cromossômico dos retroelementos (RTEs) Rex1, Rex3 e Rex6 em sete espécies do gênero Harttia e em quatro espécies do gênero Hypostomus, com o intuito de melhor compreender a organização e dinâmica dos genomas das espécies de Loricariidae. Os resultados evidenciaram um intenso acúmulo dos RTEs Rex1, Rex3 e Rex6 e distribuição dispersa em regiões heterocromáticas e eucromáticas no genoma das espécies estudadas. A presença de retroelementos em algumas regiões cromossômicas sugere sua participação em vários rearranjos cromossômicos. Além disso, o intenso acúmulo dos três retroelementos em todas as espécies de Harttia e Hypostomus, especialmente em regiões eucromáticas, pode indicar a participação destes elementos na diversificação e evolução destas espécies através da domesticação molecular pelo genoma dos hospedeiros, com estas sequências sendo co-optadas paras novas funções.(AU)

Establishment of the tax gene expression cell lines and their biological activity / 中国实验血液学杂志

This study was aimed to establish the cell lines of human T-cell leukemia virus type-1 (HTLV-1) tax gene expression and their biological activity. The eukaryotic vector pCMV-tax and pCMV-neo-Bam were transfected into Jurkat E6-1 by using liposome, following screening with G418, the tax gene expression cell line-TaxP and the negative cell lines-TaxN were selected and enriched. Then, the mRNA expressions of LAT, SLP70, ZAP70 and NF-kappaB (p65) were measured by using RT-PCR; the NF-kappaB bioactivity was tested after transfecting the pNF-kappaB-Luc plasmids into TaxP and TaxN cells; meanwhile CD25, CD69 expressions on surface of the two cell lines were tested by flow cytometry. The results showed that TaxP and TaxN cell lines were established and the tax gene expression was detected; as compared with TaxN, the mRNA expressions of LAT, SLP70 and ZAP70 in TaxP were enhanced (p<0.05), while the NF-kappaB bioactivity in TaxP cells was stronger than that in TaxN cells (p<0.01). The CD25, CD69 on TaxP cells surface was highly expressed. It is concluded that TaxP and TaxN cell lines are established, TAX protein could promote the activation of T cells and activate the NF-kappaB pathway.

El gen tax del virus linfotrópico humano tipo I en la identificación etiológica de la paraparesia espástica tropical: estudio clínico, serológico y de polimerasa en cadena en 72 pacientes / HTLV-I tax gene on the etiological identification of tropical spastic paraparesis: a clinical, serological and polymerase chain reaction study in 72 patients

Background: Tropical spastic paraparesis (TSP) is an endemic disease in Chile. In most countries, only 50 percent of patients are seropositive to HTLV-I. However, new studies suggest that seronegative TSP is also associated with HTLV-I. Aim: To describe clinical and virological features of seronegative patients with TSP. Patients and methods: seventy two chilean patients with TSP, studied by clinical, radiological and laboratory methods during 1998, are reported. The determination of antibodies to HTLV-I was accomplished by ELISA, immunofluorescence and western-blot analysis. Polymerase chain reaction for tax and 5'Ltr genes was made using primers SK 43-44, LTR1 and LTR6. Results: Thirty one patients were HTLV-I positive and 41 were negative. No clinical, radiological or laboratory differences were observed between both groups. In seropositive patients, tax and 5'ltr viral gene sequences of the HTLV-I provirus were detected in DNA of peripheral blood mononuclear cells. In seronegative cases, sequences of tax gene were detected, exclusively, in 18 of 41 patients. Conclusions: These results confirm an association with HTLV-I infection in 43,9 percent of the TSP seronegative patients. These findings support the hypothesis that a defective provirus infects peripheral blood mononuclear cells in seronegative cases of TSP. The importance tax gene in the diagnosis of the TSP is also emphasized

Detection of px gene product of bovine leukemia virus in infected cells.

Bovine leukemia virus (BLV), like its closest relatives human T-cell leukemia virus-I and II, contain a 'px' gene, between the 'env' gene and the 3' long terminal repeat in its genome. A monoclonal antibody prepared against a synthetic oligopeptide whose sequence was deduced from highly conserved region of 'px' gene of BLV, was used to detect the presence of 'px' gene product in chronically BLV infected synchronised cells. By immunoperoxidase staining the 'px' gene product was detected maximum after 6-9 hr after synchronization in the nucleus of the cells which demonstrated the close interaction of it with viral DNA which is integrated with host cell genome.