|Budget Amount *help
¥6,400,000 (Direct Cost : ¥6,400,000)
Fiscal Year 1992 : ¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1991 : ¥4,100,000 (Direct Cost : ¥4,100,000)
Although the concerted mechanism of DNA replivation and transcription has been studied by using anima virus system, that in cellular system is stil not clarified. We have used the systems including c-myc, N-myc, immunogloburin heavy chain (IgH), heat shock protein 70 (hsp70), P53, repeated sequence Alu, and SV40 to dissolve such mechanisms.
We have determined the origin of DNA replication (ori) functioning in living cells. The origins identified were located as following; 15-20 kbs upstream of the start site of transcription in c-myc gene, promoter in hsp70 gene, enhance in IgH gene, 10 kb downstream of the 11exon in p53 gene. Clones containing above regions could replicate autonomously (ARS) in mammalian cells and their regions overlapped the transcriptional regulatory regions. Thus these results clearly indicate the concerted mechanism of DNA replication initiation and transcription in mammalian cells.
We then identified the protein factors recognizing the regions described above. MSSP recognized the ori/enhancer in c-myc gene and HSBP did the promoter/ori in hsp70 gene, both of which made complexes with c-myc protein. Two cDNAs of MSSP were cloned. Oct-1 also bound to the enhancer/ori in IgH gene. In N-myc gene, 45k and 110 K proteins bound to the enhancer region acting ARS. We have also identified the protein, SOAP, which bound AT rich sequence placed in ori core of SV40, and SOAP and MSSP-1 are most probably identical each other. Alu family DNA modulated both DNA replication and transcription, and was recognized by 37 K protein. All the proteins described here bind sequenece-specifically to both double and single stranded DNA and may be involved in DNA replication and transcription.