Potential multidrug resistance gene POHL: An ecologically relevant indicator in marine sponges

• Published in: Environmental Toxicology and Chemistry
• Main Authors: Krasko, Anatoli, Kurelec, Branko, Batel, Renato, Müller, Isabel M., Müller, Werner E. G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2001
• Subjects: Arctic
• Online Access: http://dx.doi.org/10.1002/etc.5620200123; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fetc.5620200123; https://setac.onlinelibrary.wiley.com/doi/pdf/10.1002/etc.5620200123

Abstract Sponges are sessile filter feeders found in all aquatic habitats from the tropics to the arctic. Against potential environmental hazards, they are provided with efficient defense systems, e.g., protecting chaperones and/or the P‐170/multidrug resistance pump system. Here we report on a further multidrug resistance pathway that is related to the pad one homologue (POH1) mechanism recently identified in humans. It is suggested that proteolysis is involved in the inactivation of xenobiotics by the POH1 system. Two cDNAs were cloned, one from the demosponge Geodia cydonium and a second from the hexactinellid sponge Aphrocallistes vastus . The cDNA from G. cydonium , termed GCPOHL , encodes a deduced polypeptide with a size of 34,591 Da and that from A. vastus, AVPOHL , a protein of a calculated M r of 34,282. The two sponge cDNAs are highly similar to each other as well as to the known sequences from fungi ( Schizosaccharomyces pombe and Saccharomyces cerevisiae ) and other Metazoa (from Schistosoma mansoni to humans). Under controlled laboratory conditions, the expression of the potential multidrug resistance gene POHL is, in G. cydonium , strongly upregulated in response to the toxins staurosporin (20 μM) or taxol (50 μM); the first detectable transcripts appear after 1 d and reach a maximum after 3 to 5 d of incubation. The relevance of the expression pattern of the G. cydonium gene POHL for the assessment of pollution in the field was determined at differently polluted sites in the area around Rovinj (Croatia; Mediterranean Sea, Adriatic Sea). The load of the selected sites was assessed by measuring the potency of XAD‐7 concentrates of water samples taken from those places to induce the level of benzo[ a ]pyrene monooxygenase (B a PMO) in fish and to impair the multidrug resistance (MDR)/P‐170 extrusion pump in clams. These field experiments revealed that the levels of inducible B a PMO activity in fish and of the MDR potential by the water concentrates are highly correlated with the level of expression ...