CLONING, CHROMOSOME MAPPING AND EXPRESSION ANALYSIS OF THE HIRA GENE FROM DROSOPHILA-MELANOGASTER

The human HIRA gene was identified as a putative transcriptional regul ator mapping within the DiGeorge syndrome critical region at 22q11. HI RA-related proteins have been described in a number of species, but fu nctional information concerning family members is only available in Sa ccharomyces cerevisiae, where the Hir1p and Hir2p proteins are known t o be transcriptional corepressors. In order to analyse conservation of HIRA-related genes and to provide resources for functional studies in another model organism we have isolated the HIRA gene from Drosophila melanogaster (dhira). The 3374 nucleotide cDNA encodes a protein of 1 047 aa, showing 42% identity with the human protein. Alignment with th e predicted HIRA proteins from human, mouse, chick and pufferfish reve als strong conservation within the N-terminal region which contains se ven WD domains, with less conservation of C-terminal sequences. In sit u hybridisation to salivary gland chromosomes indicates that the gene resides in region 7B2-3 of the X chromosome. Dhira is expressed throug h embryonic development and at lower levels during larval and pupal de velopment. The expression of dhira is dramatically increased in early embryos and in females, suggesting that the dhira mRNA could be matern ally deposited in the embryos. (C) 1998 Academic Press.