My laboratory studies the structure-function relationships of the B-ZIP class of sequence-specific DNA binding dimeric proteins. Over 50 B-ZIP genes have been identified in the mammalian genome. In the most general terms, B-ZIP proteins both activate and repress gene expression in response to physiological changes, growth factors (FOS), stress (ATF2), neuronal signaling (CREB), or metabolic changes (CEBP). We want to study B-ZIP transcriptional function using dominant-negatives (DN's) that inhibit B-ZIP DNA binding. These dominant negatives will inhibit the DNA binding of whole families of structurally related B-ZIP proteins. This may be important as related proteins often have redundant properties. We have designed D-N, termed A-ZIPs, that inhibit B-Zip DNA binding in an equimolar competition. The A represents an N-terminal Acidic amphipathic extension of the leucine zipper that replaces the basic region critical for sequence-specific DNA binding of the B-ZIP dimer. The acidic extension heterodimerizes with the basic region of the B-ZIP motif to stabilize the complex up to 5 kcal/mol. The ZIP represents the leucine zipper that determines the specific of A-ZIP action. A related strategy also has been devised for B-HLH-ZIP proteins. We are delivering these A-ZIP's into human cells using adenovirus and into mice using tet regulable promoters. A clinical problem with cancer chemotherapy is the acquisition of drug resistance, which has been attributed to activation of MAPK pathways, including the AP-1 transcription factor. Adenovirus delivery of A-FOS, a DN that inhibits AP-1 DNA binding lowers the cisplatin concentration needed to kill a drug resistance human ovarian cell line. To examine the general utility of this observation, we infected the NCI 60 cell line screen. Several unexpected observations were made. The empty virus control is able kill all of the cells, expect the blood cells which it is not able to infect at concentrations that do not kill normal cells. The p53 expressing virus, the one being used in clinical trials is not better than the empty virus, even under conditions of genotoxic stress. AdA-FOS is better than either of these viruses. We are exploring these issues more, trying to understand what molecular properties of the cells correlate with the ease of adenovirus killing. We have recently succeeded in the regulated expression of A-CREB, A-FOS, and A-C/EBP in mice. Using either a heart or skin specific promoter, expression of these dominant negative causes death during development. We can suppress expression during development to supress lethality and express these dominant negatives in the adult. In collaboration with Dr. Yuspas group, we have shown that expression of A-FOS in the skin prevent tumor formation following a carcinogenesis procedure. If we produce tumors and then express A-FOS, the tumors die. We are using microarrays and chromatin immunopercipitation to identify the transcription targets of A-FOS that induce the transdifferentiation of squamous cells into sebaceous cells.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Investigator-Initiated Intramural Research Projects (ZIA)
Project #
Application #
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
National Cancer Institute Division of Basic Sciences
Zip Code
Golla, Jaya Prakash; Zhao, Jianfei; Mann, Ishminder K et al. (2014) Carboxylation of cytosine (5caC) in the CG dinucleotide in the E-box motif (CGCAG|GTG) increases binding of the Tcf3|Ascl1 helix-loop-helix heterodimer 10-fold. Biochem Biophys Res Commun 449:248-55
He, Ximiao; Chatterjee, Raghunath; John, Sam et al. (2013) Contribution of nucleosome binding preferences and co-occurring DNA sequences to transcription factor binding. BMC Genomics 14:428
Grontved, Lars; John, Sam; Baek, Songjoon et al. (2013) C/EBP maintains chromatin accessibility in liver and facilitates glucocorticoid receptor recruitment to steroid response elements. EMBO J 32:1568-83
Mann, Ishminder K; Chatterjee, Raghunath; Zhao, Jianfei et al. (2013) CG methylated microarrays identify a novel methylated sequence bound by the CEBPB|ATF4 heterodimer that is active in vivo. Genome Res 23:988-97
Nunez, Nomeli P; Hursting, Stephen D; Yakar, Shoshana et al. (2009) Obesity provides a permissive milieu in inflammation-associated carcinogenesis: analysis of insulin and IGF pathways. Methods Mol Biol 512:29-37
Yuan, Zhongmin; Gong, Shoufang; Luo, Jingyan et al. (2009) Opposing roles for ATF2 and c-Fos in c-Jun-mediated neuronal apoptosis. Mol Cell Biol 29:2431-42
Rozenberg, Julian; Rishi, Vikas; Orosz, Andras et al. (2009) Inhibition of CREB function in mouse epidermis reduces papilloma formation. Mol Cancer Res 7:654-64
Rozenberg, Julian M; Shlyakhtenko, Andrey; Glass, Kimberly et al. (2008) All and only CpG containing sequences are enriched in promoters abundantly bound by RNA polymerase II in multiple tissues. BMC Genomics 9:67
Paletzki, R F; Myakishev, M V; Polesskaya, O et al. (2008) Inhibiting activator protein-1 activity alters cocaine-induced gene expression and potentiates sensitization. Neuroscience 152:1040-53
Tomita, Takeshi; Kido, Taketomo; Kurotani, Reiko et al. (2008) CAATT/enhancer-binding proteins alpha and delta interact with NKX2-1 to synergistically activate mouse secretoglobin 3A2 gene expression. J Biol Chem 283:25617-27