Sucrose-induced vacuolation results in increased expression of cholesterol biosynthesis and lysosomal genes.
Mammalian cells cultured in the presence of high concentrations of sucrose demonstrate large, phase-lucent, osmotically swollen vacuoles. Three normal human fibroblast cell lines exposed to 100 mM of sucrose for 24 h demonstrated increased expression of lysosomal, intracellular vesicle trafficking, cholesterol biosynthesis, and fatty acid metabolism genes. Most steps of the cholesterol biosynthesis pathway were upregulated including HMG CoA reductase, which catalyzes the rate-limiting step of cholesterol biosynthesis. The lysosomal genes neuraminidase, CLN3, and CLCN5 and the small GTP-binding proteins Rab7L1 and Arl7 were also increased. A Rab7L1-GFP fusion protein was overexpressed in human fibroblasts and was demonstrated to localize primarily to the Golgi apparatus, and in some cells to the membranes bounding vesicles in the perinuclear region. Increased levels of the transcription factor C/EBP were found in nuclear extracts from cells exposed to sucrose for 12 h, relative to matched controls suggesting regulation of gene expression following sucrose-induced vacuolation may be coordinated, at least in part, by the transcription factor C/EBP. Sucrose-induced vacuolation is a useful model in which to study the regulation of lysosomal gene expression and biogenesis.
Helip-Wooley
Amanda
A
Hayward Human Genetics Center, Tulane University School of Medicine, New Orleans, LA 70112, USA. ahwooley@mail.nih.gov
Thoene
Jess G
JG
D002457:Cell Extracts / Q000737:chemistry; D002460:Cell Line; D002467:Cell Nucleus / Q000737:chemistry; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism; D002784:Cholesterol / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005786:Gene Expression Regulation; D006056:Golgi Apparatus / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000378:metabolism; D008247:Lysosomes / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D008562:Membrane Glycoproteins; D018832:Molecular Chaperones; D009439:Neuraminidase / Q000187:drug effects / Q000378:metabolism; D011506:Proteins / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013395:Sucrose / Q000494:pharmacology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014617:Vacuoles / Q000187:drug effects / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000187:drug effects / Q000378:metabolism
C097503:CLC-5 chloride channel; C105199:CLN3 protein, human; D002457:Cell Extracts; D018118:Chloride Channels; D005227:Fatty Acids; D008164:Luminescent Proteins; D008562:Membrane Glycoproteins; D018832:Molecular Chaperones; D011506:Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D049452:Green Fluorescent Proteins; D013395:Sucrose; D002784:Cholesterol; D009439:Neuraminidase; D020691:rab GTP-Binding Proteins