Identification of homologs of the mammalian P-glycoprotein in the mussel, Perna perna

Abstract

The ATP-binding cassette superfamily of proteins includes various ATP-driven transporters that are structurally characterized by a conserved ATP-binding domain. This family of proteins is able to transport drugs, inorganic ions, amino acids, proteins and sugars, and includes P-glycoprotein (Pgp), which is responsible for multidrug resistance in certain mammalian tumour cells. We became interested in the possible presence of Pgp homologs in Perna perna since this organism is able to survive in contaminated sites suggesting the existence of a multixenobiotic resistance mechanism. Polymerase chain reaction amplification with degenerate primers homologous to conserved regions of the Pgp protein was used to detect the presence of Pgp-like genes in genomic DNA from mussels. Amplified fragments were obtained and sequenced. Also, immunodetection of Pgp homologs was performed with the C219 monoclonal antibody. Our results confirm the existence of a gene coding for a Pgp homolog as well as the expression of a putative Pgp protein in P. perna. The mechanisms underlying the regulation of the expression of this gene are under investigation.