Transcription profiling of mouse nmyc misexpression in lung (gain of function)

ABSTRACT: Understanding how lung progenitor cells balance; proliferation against differentiation is relevant to clinical; disorders such as bronchopulmonary dysplasia of; premature babies and lung cancer. Previous studies have; established that lung development is severely disrupted in; mouse mutants with reduced levels of the proto-oncogene; Nmyc, but the precise mechanisms involved have not been; explored. We show here that Nmyc expression in the; embryonic lung is normally restricted to a distal population; of undifferentiated epithelial cells, a high proportion of; which are in the S phase of the cell cycle. Overexpression; of NmycEGFP in the epithelium under the control of; surfactant protein C (Sftpc) regulatory elements expands; the domain of S phase cells and upregulates numerous; genes associated with growth and metabolism, as shown by; transcriptional microarray. In addition, there is marked; inhibition of differentiation, coupled with an expanded; domain of expression of Sox9 protein, which is also; normally restricted to the distal epithelial compartment. By; contrast, conditional deletion of Nmyc leads to reduced; proliferation, epithelial differentiation and high levels; of apoptosis in both epithelium and mesenchyme. Unexpectedly, about 50% of embryos in which only one; copy of Nmyc is deleted die perinatally, with similarly; abnormal lungs. We propose a model in which Nmyc is; essential in the developing lung for maintaining a distal; population of undifferentiated, proliferating progenitor; cells. Experiment Overall Design: To generate Nmyc1EGF fusion protein, mouse Nmyc1 cDNA was Experiment Overall Design: inserted into the SmaI site of pEGFP (BectonDickinson), excised by Experiment Overall Design: SalI and EcoRI, and inserted into a vector containing a 3.7 kb Experiment Overall Design: promoter/enhancer of the human SFTPC gene (Wert et al., 1993). Experiment Overall Design: Transfection of 293 cells shows that the fusion protein localizes to Experiment Overall Design: the nucleus (see Fig. S1 in supplementary material). Four transgenic Experiment Overall Design: embryos were generated by pronuclear injection into Experiment Overall Design: (C57BL/6J and DBA/2J) F2 fertilized eggs. They were collected at Experiment Overall Design: E18.5, so it is not known if they would have survived postnatally. Experiment Overall Design: Duplicate samples are biological replicates.

ORGANISM(S): Mus musculus

SUBMITTER: Brian Joseph Cox 

PROVIDER: E-GEOD-6077 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress