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P-glycoprotein and sister P-glycoprotein sequences from mummichog, Fundulus heteroclitus, liver and intestine
Abstracts / Marine Environmental Research 50 (2000) 331±335
335
However, this defence is very sensitive to the presence of dierent inhibitors present in many environmental pollutants, microbial products, or extracts from polluted river and marine water. Recently, interactions between P-glycoprotein and pesticides have also been reported. This possibility directed us to assess the MXR inhibitory potential of pesticides. Using both the in vitro (cell culture) and the in vivo (mussel Dreissena polymorpha) method, we tested 16 pesticides representing several chemical classes that are used commercially in Croatia. We also investigated the MXR modulating eect of binary combinations of pesticides, and classi®ed observed eects as antagonism, additivity or synergism. Our results clearly demonstrate that several pesticides, in concentrations far below ocially established LD50 values for ®sh, exhibit a strong MXR inhibitory eect. The presence of these chemosensitizing pesticides in the environment could enhance the accumulation and toxic eects of other xenobiotics. PII: S0141-1136(00)00202-6
P-glycoprotein and sister P-glycoprotein sequences from mummichog, Fundulus heteroclitus, liver and intestine P.S. Cooper, K.S. Reece, W.K. Vogelbein, P.A. Van Veld Virginia Institute of Marine Science, The College of William and Mary, Gloucester Point, VA 23062, USA
Abstract P-glycoproteins (Pgps) responsible for eux of xenobiotics from drug-resistant and normal cells may also contribute to xenobiotic resistance in aquatic organisms. We recently reported elevation of Pgp in liver and liver tumors of mummichog (Fundulus heteroclitus) inhabiting a creosote-contaminated site (Cooper, P. S., Van Veld, P. A., & Vogelbein, W. K. (1999). Altered expression of the xenobiotic transporter P-glycoprotein in liver and liver tumors of mummichog (Fundulus heteroclitus) from a creosote-contaminated environment. Biomarkers, 4, 48±58). Here we provide sequence information on speci®c forms of Pgp in this resistant population. Reverse transcriptase-polymerase chain reaction was used to amplify overlapping cDNA fragments corresponding to the C-terminal halves of two Pgp-related sequences from liver and intestine. From liver, we ampli®ed 3 kb of a cDNA similar to mammalian sister Pgp (Spgp). We also ampli®ed 2.7 kb of another cDNA from mummichog intestine and liver that was similar to the mammalian Mdr Pgp. Analysis of these sequences con®rms that Spgps are well conserved proteins that are closely related to but distinct from true Pgps. Features of the single mummichog Mdr sequence suggest that the initial gene duplication event producing the mammalian mdr1 and mdr2 gene lineages occurred after the separation of teleost and tetrapod vertebrates. These cDNA fragments will provide useful probes for screening ®sh cDNA and genomic libraries for Pgp homologs and for gene-speci®c analysis of Pgp expression in ®sh tissues. PII: S0141-1136(00)00203-8
335
However, this defence is very sensitive to the presence of dierent inhibitors present in many environmental pollutants, microbial products, or extracts from polluted river and marine water. Recently, interactions between P-glycoprotein and pesticides have also been reported. This possibility directed us to assess the MXR inhibitory potential of pesticides. Using both the in vitro (cell culture) and the in vivo (mussel Dreissena polymorpha) method, we tested 16 pesticides representing several chemical classes that are used commercially in Croatia. We also investigated the MXR modulating eect of binary combinations of pesticides, and classi®ed observed eects as antagonism, additivity or synergism. Our results clearly demonstrate that several pesticides, in concentrations far below ocially established LD50 values for ®sh, exhibit a strong MXR inhibitory eect. The presence of these chemosensitizing pesticides in the environment could enhance the accumulation and toxic eects of other xenobiotics. PII: S0141-1136(00)00202-6
P-glycoprotein and sister P-glycoprotein sequences from mummichog, Fundulus heteroclitus, liver and intestine P.S. Cooper, K.S. Reece, W.K. Vogelbein, P.A. Van Veld Virginia Institute of Marine Science, The College of William and Mary, Gloucester Point, VA 23062, USA
Abstract P-glycoproteins (Pgps) responsible for eux of xenobiotics from drug-resistant and normal cells may also contribute to xenobiotic resistance in aquatic organisms. We recently reported elevation of Pgp in liver and liver tumors of mummichog (Fundulus heteroclitus) inhabiting a creosote-contaminated site (Cooper, P. S., Van Veld, P. A., & Vogelbein, W. K. (1999). Altered expression of the xenobiotic transporter P-glycoprotein in liver and liver tumors of mummichog (Fundulus heteroclitus) from a creosote-contaminated environment. Biomarkers, 4, 48±58). Here we provide sequence information on speci®c forms of Pgp in this resistant population. Reverse transcriptase-polymerase chain reaction was used to amplify overlapping cDNA fragments corresponding to the C-terminal halves of two Pgp-related sequences from liver and intestine. From liver, we ampli®ed 3 kb of a cDNA similar to mammalian sister Pgp (Spgp). We also ampli®ed 2.7 kb of another cDNA from mummichog intestine and liver that was similar to the mammalian Mdr Pgp. Analysis of these sequences con®rms that Spgps are well conserved proteins that are closely related to but distinct from true Pgps. Features of the single mummichog Mdr sequence suggest that the initial gene duplication event producing the mammalian mdr1 and mdr2 gene lineages occurred after the separation of teleost and tetrapod vertebrates. These cDNA fragments will provide useful probes for screening ®sh cDNA and genomic libraries for Pgp homologs and for gene-speci®c analysis of Pgp expression in ®sh tissues. PII: S0141-1136(00)00203-8