Expression and functionality of transient receptor potential melastatin 4 (TRPM4)-like channels during development of the zebrafish

Calcium signaling, from localized spikes to coordinated waves, are linked to cleavage, patterning, differentiation, and growth during embryonic development. The basis for control of these Ca2 + signals is poorly defined. In this study, the expression and functionality of the transient receptor potential melastatin 4 protein (TRPM4), an ion channel that controls Ca2 + entry into cells, was examined in the zebrafish embryo and adult. Originating with the human TRPM4 gene, Ensembl ortholog, NCBI BLAST, and Homologene searches identified a zebrafish TRPM4 “like” gene encoding a predicted protein of 1199 amino acids and sharing a 42–43% sequence identity with the mouse, rat, and human. Custom-designed zebrafish primers identified TRPM4 transcripts throughout the 0–123 h period of embryonic development with greatest and lowest relative expression at 12 and 123 h post-fertilization, respectively. Perforated patch clamp recordings in 27 h embryonic cells revealed Ca2+-activated currents with the characteristics of those described for mammalian TRPM4. Similarly, TRPM4-like expression and functionality was observed in brain and liver cells from adult fish. These findings suggest that a TRPM4-like channel is available for Ca2+ regulation during early development of the zebrafish.