Structure and function of the Groucho gene family and encoded transcriptional corepressor proteins from human, mouse, rat, Xenopus, Drosophila and nematode.

A gene family of the Groucho, TLE, ESG and AES proteins has been characterized from Drosophila, nematode, Xenopus, mouse, rat and human, and their structural relationships have been analyzed. The genomic organization of nematode ESG, human and mouse AES genes has been determined, and the expression of ESG and AES genes from Xenopus and human has been analyzed. The Groucho, TLE and ESG proteins all share a similar structure, consisting of a conserved amino-terminal domain, a variable middle region, and highly conserved carboxyl-terminal WD-40 repeats. The Drosophila Groucho transcriptional corepressor protein has been shown to interact with the DNA-binding bHLH domain of Enhancer of split, Hairy and Deadpan proteins, which proteins are involved in neurogenesis, segmentation and sex-determination, respectively. Human TLE1 protein has been demonstrated to interact with mammalian AML1 protein, which regulates hematopoiesis and osteoblast differentiation. The AES proteins from human, mouse, rat and Xenopus exhibit strong similarity to the amino-terminal domain of Groucho proteins; however, the biological function remains to be elucidated.