ASSAYS FOR IDENTIFYING GENES ENCODING SALTY TASTE RECEPTORS AND MODULATORS

摘要

The present invention relates to rationales for selecting salty taste receptors from a discrete set of taste specific genes disclosed infra by use of methods including electrophysiology, bioiirformatics, and quantitative gene expression assays using transgenic animals as well as functional assays wherein these salty taste receptors may be expressed alone or in association with other taste specific polypeptides such as TRPML3, PKD2L1 or GPRl 13. In addition the invention relates to the use of the identified salty taste receptors in assays, preferably high- throughput, in order to identify modulators which maybe used as flavor additives to modulate salty taste. Preferably, the invention provides high- throughput mammalian and medium- throughput oocyte- based electrophysiological assays for identifying human TRPML3 modulators, preferably TRPML3 enhancers. Compounds that modulate TRPML3 function in the assay are expected to affect salty taste in humans. The inventive electrophysiological assays, such as the two-electrode voltage-clamp technique, facilitate the identification of compounds which specifically modulate human TRPML3. The assays of the invention provide a robust screen useful to detect compounds that facilitate (enhance) or inhibit TRPML3 function. Compounds that enhance or block TRPML3 channel activity should thereby modulate salty taste. In addition, these compounds maybe used to regulate sodium excretion, urinary output and other biological functions relating to sodium levels. This invention relates to the elucidation that TRPML3 is involved in salty taste perception in primates including humans and likely other mammals (given the significance of sodium and other ions to physiological functions and conditions this phenotype is likely strongly conserved in different animals). The TRPML3 gene also modulates one or more of sodium metabolism, sodium excretion, blood pressure, fluid retention, cardiac function and urinary functions such as urine production and excretion.