Patent ID: 7052835

Claim:
A method of screening to identify a gene whose function is unknown previously, as a target for drug development, which comprises: (a) examining the expression of mRNAs and/or expression sequence tags being, products of gene expression before and after an event by using a high-density oligonucleotide array, and making a scatter diagram showing changes in expression levels of the mRNAs and/or expression sequence tags between before and after the event, (b) determining one or more specific mRNAs and/or expression sequence tags whose expression has changed in response to the event, from the results in the scatter diagram and from databases searches, (c) for each of said one or more mRNAs and/or expression sequence tags whose expression has changed in response to the event, designing a probe that will specifically hybridize with the mRNA and/or expression sequence tag (d) performing in situ hybridization of at least two types of tissues or cells of an organism before and after the event by using the one or more probes designed in step (c), (e) examining the localization of the one or more mRNAs and/or expression sequence tags in the tissues or cells before and after the event, (f) determining whether the localization of those mRNAs and/or expression sequence tags has changed in response to the event, and (g) identifying those mRNAs and/or expression sequence tags whose expression and localization have both changed in response to the event as a target for drug development.