title: An upstream open reading frame regulates LST1 expression during monocyte differentiation.
abstract: The regulation of gene expression depends on the interplay of multiple factors at the transcriptional and translational level. Upstream open reading frames (uORFs) play an important role as translational repressors of main ORFs and their presence or usage in transcripts can be regulated by different mechanisms. The main objective of the present study was to assess whether uORFs regulate the expression of the MHC class III gene LST1. We report that expression of LST1 is tightly regulated by alternative transcription initiation and the presence of an uORF in the 5'-UTR of transcripts. Specifically, using EGFP reporter constructs in human HeLa and HEK-293T cells and flow cytometry as well as western blot analysis we found the uORF to reduce the expression of the main ORF by roughly two-thirds. Furthermore, we were able to correlate a previously detected increase in LST1 protein expression during monocyte differentiation with an increase of transcription initiation at an alternative exon that does not contain an uORF.
authors.affiliation: Department of Biology II, Ludwig-Maximilians-Universität München, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Schiller
authors.affiliation: Department of Biology II, Ludwig-Maximilians-Universität München, Germany.
authors.forename: Carina
authors.initials: C
authors.lastname: Nowak
authors.affiliation: Department of Biology II, Ludwig-Maximilians-Universität München, Germany.
authors.forename: Kalliope N
authors.initials: KN
authors.lastname: Diakopoulos
authors.affiliation: Division Pharma, Roche Diagnostics, Penzberg, Germany.
authors.forename: Ulrich H
authors.initials: UH
authors.lastname: Weidle
authors.affiliation: Department of Biology II, Ludwig-Maximilians-Universität München, Germany.
authors.forename: Elisabeth H
authors.initials: EH
authors.lastname: Weiss
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D015153:Blotting, Western; D002454:Cell Differentiation / Q000235:genetics*; D045744:Cell Line, Tumor; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008285:Major Histocompatibility Complex / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009000:Monocytes / Q000166:cytology / Q000378:metabolism*; D016366:Open Reading Frames / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D061785:Transcription Initiation, Genetic; D020298:U937 Cells
chemical_list: D020121:5' Untranslated Regions; D047908:Intracellular Signaling Peptides and Proteins; C093604:LST1 protein, human; D008565:Membrane Proteins; D049452:Green Fluorescent Proteins