Integration of human herpesvirus 6 in a Burkitt's lymphoma cell line

Abstract

Human herpesvirus 6 (HHV‐6) genome has been found in several human lymphoid malignancies, but configuration of the HHV‐6 genome has not been well delineated. We established the HHV‐6‐positive, Epstein‐Barr virus‐negative Burkitt's lymphoma cell line Katata. In this study we investigated the status of the HHV‐6 genome in Katata cells. Neither linear nor circular HHV‐6 DNA was detected by Gardella gel analysis. The fluorescence in situ hybridization technique enabled us to directly visualize the integrated HHV‐6 DNA at the single‐cell level. Only one integrated site of viral DNA was detected in metaphase chromosomes and it was preferentially located at the long arm of chromosome 22 (22q13). Treatment of the cells with 12‐O‐tetradecanoyl‐phorbol‐13‐acetate (TPA) or with calcium ionophore A23187 led to induction of the HHV‐6 immediate‐early gene as well as the late gene. Sodium n‐butyrate also gave rise to expression of the HHV‐6 genes. The TPA inducibility was synergistically enhanced when combined with A23187 or n‐butyrate. Our study provides, for the first time, an in vitro model system of latent HHV‐6 infection whose genome is integrated into host DNA of lymphoma cells.

Lactate dehydrogenase production and release in a newly established human myeloma cell line

“…A total of 1 g of RNA was treated with 1 U of DNase I for 15 min at room temperature. RT was performed as previously described [17,22]. Briefly, 1 g of the DNase I-treated RNA was incubated in 20 l of buffer containing 50 mmol/l TrisHCl, pH 8.4, 75 mmol/l KCl, 8 mmol/l MgCl 2 , 5 mmol/l dithiotreitol, 1 mmol/l deoxynucleoside triphosphate, 50 ng of 6-mer random primer, 40 U of RNase inhibitor, and 15 U of ThermoScript reverse transcriptase (GIBCO BRL, Gaithersberg, MD) at 25°C for 10 min, followed by 50 min at 50°C.…”

Stabilization of Telomere G-Quadruplexes Interferes with Human Herpesvirus 6A Chromosomal Integration

“…HHV-6A/B integration can occur in various chromosomes, with viral genomes consistently detected in telomeric regions that are located at chromosome termini (5,10,(13)(14)(15). Telomeres are composed of double-stranded TTAGGG repeats (8 to 13 kbp long) followed by a 30-to 200-bp single-stranded 3= overhang (16)(17)(18)(19).…”

Proportion of Transcriptionally Active Dna Virus Integrants: A Meta-Analysis

“…The cell lines, both primary and established, included in the present study were: 2.2.15 [27]; AM-HLH [28]; C4-I, C4-II, CaSki [29]; CU-VI-8 [30]; EC109 [31]; HeLa [29,32]; Hep3B [27,33]; hu-GK14 [34]; HX151c, HX155c, HX156c, HX160c [35]; 37]; Katata [38]; ME-180 [29]; MS1 [39]; MS-B6, MS-T6 [40]; MS751 [29,41] Overall the present analysis identified 628 viral integrants, of which 530.84 (84.53%) were transcriptionally active; in other words, 15.47% of the integrants were silent. One study regarding HHV-4 reported that 90-92% of the integrants in the screened cells were active [36]; the higher level was used herein to report the proportion of active viral centers, hence the fractional number.…”

“…These studies also highlighted the absence of both immune response against HBsAg and signs of hepatitis in the progeny of the transfected mice; the viral antigen was postulated to be recognized as self in the mice and therefore no immune response was activated that could damage the liver. Vertical transmission in mice of integrated HBV was reported [56].A selectable HHV-6 integrant was activated using either 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or calcium ionophores [38]. This was obtained in the cell line Katata, which was derived from a Burkitt's lymphoma sample.…”