GPX-GI is a cytosolic tetrameric Se-dependent glutathione peroxidase, similar in properties to GPX-1. Unlike the almost ubiquitous GPX-1, GPX-GI is mainly expressed in the epithelium of gastrointestinal tract. GPX-GI ...GPX-GI is a cytosolic tetrameric Se-dependent glutathione peroxidase, similar in properties to GPX-1. Unlike the almost ubiquitous GPX-1, GPX-GI is mainly expressed in the epithelium of gastrointestinal tract. GPX-GI contributes to at least fifty percent of GPX activity in rodent small intestmal epithelium. The total GPX activity consists of at least 70% of selenium-dependent GPX activity in this compartment.By analyzing a panel of mouse mterspecies DNA from the Jackson Laboratory's backcross resource,we mapped Gpx2 gene to mouse chromosome 12 between D12Mit4 and D12Mit5, near the Ccs1 locus which contains a colon cancer susceptibility gene. A pseudogene, Gpx2-ps is mapped to mouse chromosome 7.Comparison of Gpx2 gene expression in three pairs of C57BL/6Ha and ICR/Ha mice which are respectively resistant and sensitive to dimethylhydrazine-induced colon cancer, we found a higher Gpx2 mRNA level in C57BL/6Ha colon than ICR/Ha colon. Interestingly, a lower level of GPX activity is found in the resistant strain of mice. Because GPX-1 has three times higher specific activity than GPX GI, our data suggest that the decreased GPX activity may result from a higher level of Gpx2 gene expression in those cells co-express GPx1 gene展开更多
Five to ten serotyqe I Marek’s disease virus (MDV1) strains of different pathotypes were compared for their DNA sequences of gI, gE, pp38 and meq genes. The reference strains were vMDV GA and JM, vvMDV RB1B and Md11(...Five to ten serotyqe I Marek’s disease virus (MDV1) strains of different pathotypes were compared for their DNA sequences of gI, gE, pp38 and meq genes. The reference strains were vMDV GA and JM, vvMDV RB1B and Md11(p16), vv+MDV strains 648A and 584A,vaccine strain CVI988/Rispens; Chinese strains were: v MDV strain N, vvMDV strain G2, vaccine strain 814. Only random aa changes were found in 12 positions within gE of 497 aa among 10 analyzed strains and in 10 positions within gI of 355 aa among 5 strains. There was no relationship found between virus pathotypes and aa changes of both glycoproteins. The aa changes happened in 14 positions within meq of 339 aa among 5 compared strains. But a proline deletion at aa #194 in a proline-rich domain of meq were shared by two vaccine strains CVI988/Rispens and 814, the latter was a non-pathogenic vaccine strain of serotype 1 isolated in 1983 in China. In another hand, vv+MDV strains 648A demonstrated 5 unique aa changes and 4 of them also located in the proline-rich region. The pp38 was very conservative among sequenced 10 strains, there were only two positions at #107 and #109 with aa altered in its 290 aa. All tested MDV1 strains had glutamine at #107, instead, only vaccine CVI988 had arginine at the position and lost its epitope reactive with Mab H19, to which all other tested MDV1 strains were positive. However, CVI988 and vMDV GA shared a Mab T65-recognized epitope when there was glycine at aa#109. It was glutamic acid at aa#109 in all other MDV1 strains which were not reactive with Mab T65. It seems like that there is some relationship between pathotypes and sequences of pp38 and meq, but more strains need to be compared.展开更多
文摘GPX-GI is a cytosolic tetrameric Se-dependent glutathione peroxidase, similar in properties to GPX-1. Unlike the almost ubiquitous GPX-1, GPX-GI is mainly expressed in the epithelium of gastrointestinal tract. GPX-GI contributes to at least fifty percent of GPX activity in rodent small intestmal epithelium. The total GPX activity consists of at least 70% of selenium-dependent GPX activity in this compartment.By analyzing a panel of mouse mterspecies DNA from the Jackson Laboratory's backcross resource,we mapped Gpx2 gene to mouse chromosome 12 between D12Mit4 and D12Mit5, near the Ccs1 locus which contains a colon cancer susceptibility gene. A pseudogene, Gpx2-ps is mapped to mouse chromosome 7.Comparison of Gpx2 gene expression in three pairs of C57BL/6Ha and ICR/Ha mice which are respectively resistant and sensitive to dimethylhydrazine-induced colon cancer, we found a higher Gpx2 mRNA level in C57BL/6Ha colon than ICR/Ha colon. Interestingly, a lower level of GPX activity is found in the resistant strain of mice. Because GPX-1 has three times higher specific activity than GPX GI, our data suggest that the decreased GPX activity may result from a higher level of Gpx2 gene expression in those cells co-express GPx1 gene
文摘Five to ten serotyqe I Marek’s disease virus (MDV1) strains of different pathotypes were compared for their DNA sequences of gI, gE, pp38 and meq genes. The reference strains were vMDV GA and JM, vvMDV RB1B and Md11(p16), vv+MDV strains 648A and 584A,vaccine strain CVI988/Rispens; Chinese strains were: v MDV strain N, vvMDV strain G2, vaccine strain 814. Only random aa changes were found in 12 positions within gE of 497 aa among 10 analyzed strains and in 10 positions within gI of 355 aa among 5 strains. There was no relationship found between virus pathotypes and aa changes of both glycoproteins. The aa changes happened in 14 positions within meq of 339 aa among 5 compared strains. But a proline deletion at aa #194 in a proline-rich domain of meq were shared by two vaccine strains CVI988/Rispens and 814, the latter was a non-pathogenic vaccine strain of serotype 1 isolated in 1983 in China. In another hand, vv+MDV strains 648A demonstrated 5 unique aa changes and 4 of them also located in the proline-rich region. The pp38 was very conservative among sequenced 10 strains, there were only two positions at #107 and #109 with aa altered in its 290 aa. All tested MDV1 strains had glutamine at #107, instead, only vaccine CVI988 had arginine at the position and lost its epitope reactive with Mab H19, to which all other tested MDV1 strains were positive. However, CVI988 and vMDV GA shared a Mab T65-recognized epitope when there was glycine at aa#109. It was glutamic acid at aa#109 in all other MDV1 strains which were not reactive with Mab T65. It seems like that there is some relationship between pathotypes and sequences of pp38 and meq, but more strains need to be compared.
