It is intended to provide a novel gene encoding a new protein which interacts with BMAL2 protein. Namely, a novel gene comprising any one of the following DNAs (a) to (e): (a) a DNA comprising any one of the base sequences represented by SEQ ID NOS: 1 to 4; (b) a DNA that comprises a base sequence derived from the base sequence of the DNA (a) by deletion, substitution or addition of one to several bases and encodes a protein interacting with BMAL2 protein; (c) a DNA that comprises a base sequence derived from the base sequence of the DNA (a) by deletion, substitution or addition of one to several bases and is hybridizable with the DNA (a) under stringent conditions; (d) a DNA that comprises a base sequence derived from the base sequence of the DNA (a) by deletion, substitution or addition of one to several bases and has a homology of 90% or higher with the DNA (a); and (e) a DNA comprising a base sequence that is complementary to any one of the DNAs (a) to (d).