Generation and characterization of an inducible transgenic model for studying mouse esophageal biology.
BACKGROUND
To facilitate the in vivo study of esophageal (stem) cell biology in homeostasis and cancer, novel mouse models are necessary to elicit expression of candidate genes in a tissue-specific and inducible fashion. To this aim, we developed and studied a mouse model to allow labeling of esophageal cells with the histone 2B-GFP (H2B-GFP) fusion protein.


RESULTS
First, we generated a transgenic mouse model expressing the reverse tetracycline transactivator rtTA2-M2 under control of the promoter (ED-L2) of the Epstein-Barr virus (EBV) gene encoding the latent membrane protein-1 (LMP-1). The newly generated ED-L2-rtTA2-M2 (ED-L2-rtTA) mice were then bred with the previously developed tetO-HIST1H2BJ/GFP (tetO-H2B-GFP) model to assess inducibility and tissue-specificity. Expression of the H2B-GFP fusion protein was observed upon doxycycline induction but was restricted to the terminally differentiated cells above the basal cell layer. To achieve expression in the basal compartment of the esophagus, we subsequently employed a different transgenic model expressing the reverse transactivator rtTA2S-M2 under the control of the ubiquitous, methylation-free CpG island of the human hnRNPA2B1-CBX3 gene (hnRNP-rtTA). Upon doxycycline administration to the compound hnRNP-rtTA/tetO-H2B-GFP mice, near-complete labeling of all esophageal cells was achieved. Pulse-chase experiments confirmed that complete turnover of the esophageal epithelium in the adult mouse is achieved within 7-10 days.


CONCLUSIONS
We show that the esophagus-specific promoter ED-L2 is expressed only in the differentiated cells above the basal layer. Moreover, we confirmed that esophageal turn-over in the adult mouse does not exceed 7-10 days.
Department of Pathology, Josephine Nefkens Institute, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
Sabrina
S
Roth
Patrick
P
Franken
Kim
K
Monkhorst
John
J
Kong a San
Riccardo
R
Fodde
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics; D004848:Epithelium / Q000378:metabolism; D004947:Esophagus / Q000166:cytology / Q000378:metabolism*; D005260:Female; D005818:Genetic Engineering; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000235:genetics; D006657:Histones / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D007633:Keratins / Q000378:metabolism; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics; D015533:Transcriptional Activation
C518294:CBX3 protein, human; D002868:Chromosomal Proteins, Non-Histone; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D006657:Histones; D019394:Ki-67 Antigen; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; C439768:hnRNP A2; D049452:Green Fluorescent Proteins; D007633:Keratins