Characterization of human deoxyribonuclease I gene (DNASE1) promoters reveals the utilization of two transcription-starting exons and the involvement of Sp1 in its transcriptional regulation.
Levels of deoxyribonuclease I (DNase I) activity in vivo have been shown to be altered by physiological and/or pathological processes. However, no information is available on the regulation of DNase I gene (DNASE1) expression in vivo or in vitro. We first mapped the transcription start sites of DNASE1 in human pancreas and in the DNase I-producing human pancreatic cancer cell line QGP-1, and revealed a novel site approximately 12 kb upstream of exon 1, which was previously believed to be the single transcription-starting exon. This initiation site marks an alternative starting exon, designated 1a. Exons 1 and 1a were used simultaneously as transcription-starting exons in pancreas and QGP-1 cells. Promoter assay, EMSA and chromatin immunoprecipitation analysis with QGP-1 cells showed the promoter region of exon 1a in which the Sp1 transcription factor is specifically involved in promoter activity. This is the first to be identified as a transcription factor responsible for gene expression of vertebrate DNase I genes. Furthermore, RT-PCR analysis indicated alternative splicing of human DNASE1 pre-mRNA in pancreas and QGP-1 cells. Only two transcripts among eight alternative splicing products identified can be translated to produce intact DNase I protein. These results suggest that human DNASE1 expression is regulated through the use of alternative promoter and alternative splicing.
Kominato
Yoshihiko
Y
Department of Legal Medicine and Medical Genetics, Gunma University, Japan.
Ueki
Misuzu
M
Iida
Reiko
R
Kawai
Yasuyuki
Y
Nakajima
Tamiko
T
Makita
Chikako
C
Itoi
Masako
M
Tajima
Yutaka
Y
Kishi
Koichiro
K
Yasuda
Toshihiro
T
D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002522:Chlorocebus aethiops; D003850:Deoxyribonuclease I / Q000235:genetics* / Q000378:metabolism; D005091:Exons; D005786:Gene Expression Regulation; D006801:Humans; D008969:Molecular Sequence Data; D010190:Pancreatic Neoplasms / Q000235:genetics; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic
D012333:RNA, Messenger; D016329:Sp1 Transcription Factor; D003850:Deoxyribonuclease I