RESUMEN
Mono(ADP-ribosyl)transferases regulate the function of target proteins by attaching ADP-ribose to specific amino acid residues in their target proteins. The purpose of this study was to determine the structure, chromosomal localization, and expression profile of the gene for mouse ecto-ADP-ribosyltransferase ART5. Southern blot analyses indicate that Art5 is a single copy gene which maps to mouse chromosome 7 at offset 49.6 cM in close proximity to the Art1, Art2a and Art2b genes. Northern blot and RT-PCR analyses demonstrate prominent expression of Art5 in testis, and lower levels in cardiac and skeletal muscle. Sequence analyses reveal that the Art5 gene encompasses six exons spanning 8 kb of genomic DNA. The 5' end of the Art5 gene overlaps with that of the Art1 gene. A single long exon encodes the predicted ART5 catalytic domain. Separate exons encode the N-terminal leader peptide and a hydrophilic C-terminal extension. Sequencing of RT-PCR products and ESTs identified six splice variants. The deduced amino acid sequence of ART5 shows 87% sequence identity to its orthologue from the human, and 37 and 32% identity to its murine paralogues ART1 and ART2. Unlike ART1 and ART2, ART5 lacks a glycosylphosphatidylinositol-anchor signal sequence and is predicted to be a secretory enzyme. This prediction was confirmed by transfecting an Art5 cDNA expression construct into Sf9 insect cells. The secreted epitope-tagged ART5 protein resembled rat ART2 in exhibiting potent NAD-glycohydrolase activity. This study provides important experimental tools to further elucidate the function of ART5.
Asunto(s)
ADP Ribosa Transferasas/genética , Genes/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Northern Blotting , Línea Celular , Mapeo Cromosómico , ADN/química , ADN/genética , ADN Complementario/química , ADN Complementario/genética , Exones , Femenino , Expresión Génica , Intrones , Isoenzimas/genética , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos , Datos de Secuencia Molecular , Muridae , ARN Mensajero/genética , ARN Mensajero/metabolismo , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Distribución TisularRESUMEN
To prevent the development of acute graft-versus-host disease (GVHD) in lethally irradiated C57BL/6 (H-2b) recipient mice transplanted with bone marrow-splenocyte grafts from major histocompatibility complex (MHC) disparate BALB/c mice (H-2d), recipient mice were treated with the rationally designed JAK3 inhibitor WHI-P131 [4-(4'-hydroxyphenyl)-amino-6,7-dimethoxyquinazoline] (20 mg/kg, 3 times a day [tid]) daily from the day of bone marrow transplantation (BMT) until the end of the 85-day observation period. Total body irradiation (TBI)-conditioned, vehicle-treated control C57BL/6 mice (n = 38) receiving bone marrow-splenocyte grafts from BALB/c mice survived acute TBI toxicity, but they all developed histologically confirmed severe multi-organ GVHD and died after a median survival time of 37 days. WHI-P131 treatment (20 mg/kg intraperitoneally, tid) prolonged the median survival time of the BMT recipients to 56 days. The probability of survival at 2 months after BMT was 11% +/- 5% for vehicle-treated control mice (n = 38) and 41% +/- 9% for mice treated with WHI-P131 (n = 32) (P <.0001). Notably, the combination regimen WHI-P131 plus the standard anti-GVHD drug methotrexate (MTX) (10 mg/m2 per day) was more effective than WHI-P131 or MTX alone. More than half the C57BL/6 recipients receiving this most effective GVHD prophylaxis remained alive and healthy throughout the 85-day observation period, with a cumulative survival probability of 70% +/- 10%. Taken together, these results indicate that targeting JAK3 in alloreactive donor lymphocytes with a chemical inhibitor such as WHI-P131 may attenuate the severity of GVHD after BMT.