AI Article Synopsis

  • Cathepsin E (CE) is an important protein found mainly in specific cells like those in the digestive system and blood, but how it is regulated in these cells is not fully understood.
  • Researchers identified multiple starting points for the CE gene's transcription in gastric adenosarcoma cells, discovering a significant non-coding region upstream that may influence its expression.
  • The study highlighted that the transcription factor Sp1 has a key role in regulating CE gene expression, as evidenced by experiments showing its binding to the CE gene promoter and its impact on increasing CE protein levels.

Article Abstract

Cathepsin E (CE) is an intracellular aspartic proteinase that is exclusively expressed in cells of the gastrointestinal tracts, lymphoid tissues, urinary organs and red blood cells. However, the molecular mechanism by which CE is predominantly expressed in these cells remains unknown. Here, we report the identification of several transcription start sites of the CE gene and their regulatory factors in gastric adenosarcoma cells. We first identified several unique transcription start sites in mouse CE genes by an oligo cap method. Their analysis also revealed the existence of a non-coding region ∼24-kb upstream of exon 1 in the CE gene and also the existence of two transcripts for CE. Luciferase analyses in upstream of exon 1 revealed that this site contained putative binding regions for the transcription factors Sp1, AP-1 and cEts-1 essential for the expression of CE gene. Moreover, electrophoretic mobility shift assays revealed that the protein-oligonucleotides complex of the Sp1 site were supershifted by an anti-Sp1 antibody. The chromatin immunoprecipitation assay showed that Sp1 bound to the CE promoter region. In addition, overexpression of the Sp1 protein increased the expression of the CE protein. Altogether, these results suggest that Sp1 binding plays a particularly important role in the regulation of CE gene expression.

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Source
http://dx.doi.org/10.1093/jb/mvr135DOI Listing

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