Abstract: The present invention relates to a mutant of human ?-N-acetylglucosaminidase (hNAGLU), more specifically a hNAGLU mutant produced by adding a mutation to an amino acid sequence for hNAGLU such that an expression level of hNAGLU in a host cell in which a gene encoding hNAGLU is introduced can be increased compared with the case where a gene encoding wild-type hNAGLU is introduced. For example, the hNAGLU mutant has an amino acid sequence represented by SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 15, or SEQ ID NO: 19, or has an amino acid sequence introduced a mutation to the amino acid sequence of any one of the hNAGLU mutants.

Abstract: A novel human tumor suppressor gene coding for a tumor suppressor protein and whose expression is inhibited by human growth hormone. The DNA composing the gene, and the protein coded by the gene are also provided. The DNA has a nucleotide sequence set forth under SEQ ID NO:1 or SEQ ID NO:2 in the Sequence Listing.