This invention provides a method for obtaining a gene involved in
regulation of cartilage differentiation, in which a transcription factor,
preferably Runx2/Cbfa1, is forcedly expressed in a cell that is deficient
such transcription factor, preferably in a Runx2/Cbfa1-deficient
chondrocyte, and the gene, the expression of which is thereby induced, is
selected using DNA chip analysis, subtraction, or other means as well as
a Runx2/Cbfa1-deficient chondrocyte useful for carrying out such method.
The invention also provides a polynucleotide obtained by such method, a
polypeptide encoded by such polynucleotide, an antibody against such
polypeptide, a recombinant vector comprising such polynucleotide, a
transformant comprising such recombinant DNA vector, a cell expressing
such polypeptide, a transgenic animal of such polynucleotide, an animal
model of a bone and/or joint disease (preferably osteoarthritis), a
method for screening for a therapeutic agent and/or prophylactic agent
for a bone and/or joint disease (preferably osteoarthritis) using the
aforementioned objects, a candidate compound for a therapeutic agent
and/or prophylactic agent selected by such method, a pharmaceutical
composition for a bone and/or joint disease (preferably osteoarthritis),
and a method for diagnosing such disease.