Chip-on-chip analysis of direct Nkx2.1 target genes in proliferating and differentiating epithelium in mouse lung development.

ABSTRACT: Nkx2.1 is a critical regulator of mammalian lung development. It is expressed in epithelial cells at the initiation of lung organogenesis, becoming progressively restricted during development to bronchiolar and alveolar type II epithelial cells. In humans, it is a common marker of carcinomas of lung and thyroid origin and is highly amplified in 10-15% of lung adenocarcinomas. Despite its key role in development and disease only a few genes directly regulated by Nkx2.1 are known. To identify direct Nkx2.1target genes and pathways controlled by this transcription factor in vivo we analyzed, by chromatin immuno-precipitation (chip)-on-chip method, Nkx2.1 binding to DNA cis-elements in developing mouse lung. We analyzed embryonic day E11.5 lungs, when Nkx2.1 expressing cells are undergoing predominantly proliferation, and day E19.5, when Nkx2.1 expressing cells are undergoing predominantly differentiation. Many highly bound targets are known and well described, such as surfactant proteins and secretoglobins. Unique or common target genes involved in a variety of developmental and tumorigenic pathways were identified at each developmental time point. Positive regulation of cell proliferation was the highest overrepresented biological process at E11.5 while ion transport was the highest overrepresented biological process at E19.5. New identified targets include proliferation related genes such as E2F3, Met, Ccnb1, and Ccnb2. Nkx2.1 downregulation in mouse epithelial and human carcinoma cell lines reduced cell proliferation by arresting cells in the G2/M phase. Reduced expression of Nkx2.1 target genes in both cell lines supports a direct role of Nkx2.1 in regulation of cell proliferation genes. The identification of these transcriptional regulatory pathways in vivo aid us to understand Nkx2.1 function in lung development and link it to disease, since many of the identified targets are aberrantly up regulated in cancer cells. Developing mouse lung, 2 developmental time points E11.5 and E19.5, genomic DNA fragments immunoprecipitated with a-Nkx2.1 (07-601, Upstate-Millipore) vs input, E11.5, 2 biological replicates and E19.5, 3 biological replicates

ORGANISM(S): Mus musculus

SUBMITTER: Maria Ramirez 

PROVIDER: E-GEOD-23043 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress