Ids are dominant-negative helix-loop-helix (HLH) proteins that play overlapping yet distinct
roles in antagonizing basic HLH transcription factors. Although Ids affect myogenesis,
neurogenesis, and B-cell development, little is known about theirin vivo functions in
epithelia. We have examined the effects of forced expression of Id-1 in the small intestinal
epithelium of adult chimeric mice. 129/Sv embryonic stem cells, transfected with DNA
containing Id-1 under the control of transcriptional regulatory elements that function in all …