Cloning and Determination of Tissue Specific Expression Pattern of Astacus Leptodactylus Na+ Ca 2+ Exchanger Gene

Abstract

Cytosolic Ca2+ plays an essential role in various cellular functions. Changes in cytosolic Ca2+ concentration is important for different cellular activities like muscle contraction and neurotransmitter release. A set of channels and exchangers are responsible for maintenance of resting calcium concentration and the generation of the calcium transient. Na+/Ca2+ exchanger can move Ca2+ in either direction depending on net electrochemical driving force acting on the exchanger. Structure and function of Na+/Ca2+ exchanger is conserved within the animal kingdom. In the crayfish there are some recent functional studies indicating the presence of Na+/Ca2+ exchanger. However, there is no report focusing onto genetic and molecular properties of the crayfish exchanger yet. To reveal properties of the crayfish Na+/Ca2+ exchanger gene, various molecular techniques have been employed by considering the homology observed among closely related species. As a result, the complete coding sequence of the putative crayfish Na+/Ca2+ exchanger gene has been revealed. Corresponding amino acid sequence has been found to be 58 – 65 % similar to known Na+/Ca2+ exchangers, sharing characteristics of the exchanger protein family. Tissue specific expression pattern of crayfish Na+/Ca2+ exchanger gene indicates that exchanger is expressed in excitable or biologically active tissues like ganglia, muscle and antennal gland while its expression is almost absent in gill which passively filters the neighboring fluid. Future efforts will be dedicated to define structure-function relationship of the discovered gene.