Cloning and Characterization of a Novel Zinc Finger Transcriptional Repressor

Abstract

We have identified a novel transcriptional repressor, AEBP2, that binds to a regulatory sequence (termed AE-1) located in the proximal promoter region of the aP2 gene that encodes the adipose fatty acid-binding protein. Sequence analysis of AEBP2 cDNA revealed that it encodes a protein containing three Gli-Krü ppel (Cys 2 -His 2 )-type zinc fingers. Northern blot analysis revealed two transcripts (4.5 and 3.5 kilobases) which were ubiquitously expressed in every mouse tissue examined. In co-transfection assays, AEBP2 repressed transcription from the homologous aP2 promoter containing multiple copies of the AE-1 sequence. Moreover, a chimeric construct encoding a fusion AEBP2 protein with the Gal4 DNA-binding domain was able to repress the transcriptional activity of a heterologous promoter containing the Gal4-binding sequence. The transcriptional repression function of AEBP2 was completely abolished when one of the conserved histidine residues and a flanking serine residue in the middle zinc finger were replaced with an arginine residue. The defective transcriptional repression function of the mutant derivative was due neither to lack of expression nor to a failure to localize to the nucleus. Moreover, both the wild-type and mutant derivative of either the histidinetagged recombinant AEBP2 proteins or the in vitro translated Gal4-AEBP2 fusion proteins were equally able to bind to the target DNA. These results suggest that a portion of the zinc finger structure may play a direct role in transcriptional repression function, but not in DNA binding.

Tumor-specific adenoviral gene therapy: transcriptional repression of gene expression by utilizing p53-signal transduction pathways

“…[18][19][20][21][22][23][24][25][26]55,56 The KRAB-domain represses the activity of CMV-promoter through direct communications with TATA box-dependent basal transcription machinery, 18,55 whereas mSIN3B interacts with essential DNAbinding proteins that place it in a promoter context in which it can repress transcription by recruiting proteins that condense chromatin by histone deacetylation. 19 In contrast to KRAB-A or mSIN3B, the Zik1-repressor domain does not repress gene transcription from the CMV gal -promoter and some of the other repressor domains showed only weak repression of CMV galactivity.…”

“…Expression vectors for repressor fusion proteins of GAL4-DBD were kindly provided by: L Lania, Neaples, Italy (KRAB-A), 18 RA DePinho Boston, USA (m-SIN3B-SF and m-SIN3B-LF), 19 DJ Hall, Philadelphia, PA, USA (ZF87/MAZ), 20 K Bomsztyk, Seattle, USA (ZIK1), 21 LM Staudt, Bethesda, MD, USA (BCL-6), 22 C Bartholomew, Glasgow, Scotland (EVI-1), 23 Y Shi, Boston, USA (YY), 24 H-S Ro, Halifax Canada (AEBP2) 25 and A Bird, Edinburgh, UK (MeCP2 170-310 and MeCP2 209-492). 26 …”

Identification of Glis1, a Novel Gli-related, Krüppel-like Zinc Finger Protein Containing Transactivation and Repressor Functions

“…ZFDs have been implicated in many functions, including DNA recognition, protein/protein interactions, transcriptional repression, and nuclear localization (52)(53)(54)(55)(56). Examination of the secondary structure of the Glis1 zinc finger domain indicated that the second half of each zinc finger consists of an ␣-helix.…”

Glial and Neuronal Functions of the Drosophila Homolog of the Human SWI/SNF Gene ATR-X (DATR-X) and the jing Zinc-Finger Gene Specify the Lateral Positioning of Longitudinal Glia and Axons

“…The C 2 H 2 zinc fingers of Jing are most similar (50% identical) to those of the mouse adipocyte enhancer binding protein 2 (AEBP2) and also show 25% homology to those of the Krü ppel family of transcription factors, including those encoding gli and ZIC2 (Liu and Montell 2001). AEBP2 function is implicated in chromatin remodeling events (Cardoso et al 1998;Cao and Zhang 2004) and has strong expression in the brain (He et al 1999).…”