Abstract: It is intended to provide a sodium-independent transporter carrying an acidic amino acid and its gene. A protein having the amino acid sequence represented by SEQ ID NO: 1 and being capable of sodium-independently transporting an acidic amino acid and its analogs; a gene encoding this protein; a fused protein of the above protein with an auxiliary factor enabling the expression of its function; a gene encoding the same; a method of analyzing the function of a transporter using the same: and utilization thereof.