A natural antisense transcript regulates Zeb2/Sip1 gene expression during Snail1-induced epithelial-mesenchymal transition.
Expression of Snail1 in epithelial cells triggers an epithelial-mesenchymal transition (EMT). Here, we demonstrate that the synthesis of Zeb2, a transcriptional repressor of E-cadherin, is up-regulated after Snail1-induced EMT. Snail1 does not affect the synthesis of Zeb2 mRNA, but prevents the processing of a large intron located in its 5'-untranslated region (UTR). This intron contains an internal ribosome entry site (IRES) necessary for the expression of Zeb2. Maintenance of 5'-UTR Zeb2 intron is dependent on the expression of a natural antisense transcript (NAT) that overlaps the 5' splice site in the intron. Ectopic overexpression of this NAT in epithelial cells prevents splicing of the Zeb2 5'-UTR, increases the levels of Zeb2 protein, and consequently down-regulates E-cadherin mRNA and protein. The relevance of these results is demonstrated by the strong association between NAT presence and conservation of the 5'-UTR intron in cells that have undergone EMT or in human tumors with low E-cadherin expression. Therefore, the results presented in this article reveal the existence of a NAT capable of activating Zeb2 expression, explain the mechanism involved in this activation, and demonstrate that this NAT regulates E-cadherin expression.
Beltran
Manuel
M
Programa de Recerca en Càncer, Institut Municipal d'Investigació Mèdica (IMIM)-Hospital del Mar, Barcelona 08003, Spain.
Puig
Isabel
I
Peña
Cristina
C
García
José Miguel
JM
Alvarez
Ana Belén
AB
Peña
Raúl
R
Bonilla
Félix
F
de Herreros
Antonio García
AG
D020121:5' Untranslated Regions; D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D015153:Blotting, Western; D015820:Cadherins / Q000235:genetics* / Q000378:metabolism; D016022:Case-Control Studies; D002460:Cell Line; D002478:Cells, Cultured; D003106:Colon; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology; D017931:DNA Primers; D004848:Epithelium / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008648:Mesoderm / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids; D011401:Promoter Regions, Genetic; D016372:RNA, Antisense / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000378:metabolism*; D000074165:Zinc Finger E-box Binding Homeobox 2; D016335:Zinc Fingers
D020121:5' Untranslated Regions; D015820:Cadherins; D017931:DNA Primers; C108381:GEMIN2 protein, human; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D016372:RNA, Antisense; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; C000604407:SNAI1 protein, human; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; C492363:ZEB2 protein, human; D000074165:Zinc Finger E-box Binding Homeobox 2