tailieunhanh - Báo cáo khoa học: Alternative initiation of transcription of the humanpresenilin 1gene in SH-SY5Y and SK-N-SH cells The role of Ets factors in the regulation ofpresenilin 1

We have identifiedDNA sequences required for the expres-sion of thepresenilin 1(PS1) gene. A promoter region has been mapped in SK-N-SH cells and includes sequences be-tween)118and+178flankingthemajor initiationsite (+1). ThePS1gene is also efficiently transcribed in the SH-SY5Y subclone of SK-N-SH cells. However the promoter appears tobeutilized inalternativeways inbothcell types. Sequences both upstream as well as downstream from the initiation site mapped in SK-N-SH cells were shown by 5¢-and3¢-deletion analysis to play a crucial role in both cell lines | Eur. J. Biochem. 271 4485-4494 2004 FEBS 2004 doi Alternative initiation of transcription of the human presenilin 1 gene in SH-SY5Y and SK-N-SH cells The role of Ets factors in the regulation of presenilin 1 Martine Pastorcic1 and Hriday K. Das1 2 3 1 Department of Pharmacology Neuroscience 2Department of Molecular Biology Immunology and3Institute of Cancer Research University of North Texas Health Science Center at Fort Worth TX USA We have identified DNA sequences required for the expression of the presenilin 1 PS1 gene. A promoter region has been mapped in SK-N-SH cells and includes sequences be-tween-118and 178 flankingthe major initiation site 1 . The PS1 gene is also efficiently transcribed in the SH-SY5Y subclone of SK-N-SH cells. However the promoter appears to be utilized in alternative ways in both cell types. Sequences both upstream as well as downstream from the initiation site mapped in SK-N-SH cells were shown by 5 - and 3 -deletion analysis to play a crucial role in both cell lines. However in SH-SY5Y cells either upstream or downstream sequences are sufficient to direct transcription whereas in SK-N-SH cells 5 -deletions past the 1 site eliminate over0 95 of transcription. Several Ets motifs GGAA as well as Sp1 motifs G T GGCGGRRY are juxtaposed both upstream and downstream from 1. To understand how the promoter may be utilized alternatively in different cell types we have examined the effect of point mutations in these elements. Altering an Ets motif at -10 eliminates 80 of transcription in SK-N-SH cells whereas the same mutation has only a minor effect in SH-SY5Y cells. Conversely mutation of the Ets element at 90 which eliminates 70 of transcription in SH-SY5Y cells has a lesser effect in SK-N-SH cells. In both cell types a promoter including mutations at both -10 and 90 sites loses over 90 transcription activity indicating the crucial importance of these two Ets motifs. The effect of Sp1 mutations appears to be .