During development and maintenance of tissues there is a balance between cell division and cell death in order to generate the proper number and type of cells in the animal. This process includes the elimination by programmed cell death (PCD) or apoptosis of cells that are harmful or not longer needed. Genes that function as effectors or suppressors of the PCD pathway have been identified in Caenorhabditis elegans. Within mammalian systems, the bcl-2 proto-oncogene has been shown to serve as a suppressor of PCD. However, Bcl-2 failed to block several forms of PCD arguing that certain cell deaths are independent of Bcl-2. We have identified a novel gene, bcl-x, that functions as a dominant regulator of apoptotic cell death in vertebrates including humans. The coding region of bcl-x displays extensive amino acid homology with Bcl-2. Two forms of the Bcl-x protein, Bcl-x1 and Bcl-xs, are expressed in human cells by alternative splicing of the bcl-x mRNA. Bcl-x1 is a powerful repressor of PCD as demonstrated by gene transfer experiments. By contrast, Bcl-xs is a facilitator of cell death by inhibiting the death suppressor activity of Bcl-2 and perhaps Bcl-x1. Importantly, the expression of both bcl-x1 and bcl-xs mRNA is highly regulated in the resting state in tissues and during cell activation arguing that bcl-x plays an important role in determining cell fate in the animal. The current proposal will focus on the murine bcl-x to enable us to assess in detail its developmental regulation and biological function. The murine full-length cDNA has been isolated and sequenced. Genomic clones encompassing the bcl-x locus have been isolated. Furthermore, antibodies directed against the murine Bcl-x proteins and a panel of stable bcl-x transfectants have been developed.
The specific aims of the present application are to (i) define the genomic organization and establish the chromosomal localization of the mouse bcl-x gene (ii) examine the expression of Bcl-x1 and Bcl-xs in tissues and their subcellular location (iii) to identify interaction between Bcl-x proteins and cellular proteins including Bcl-2 and (iv) target bcl-x transgenes to B cells to examine their biological role in the animal. Beyond its critical role in regulating physiological cellular processes. genes that control the PCD pathway such as bcl-2 and bcl-x have been implicated in the pathogenesis of B-cell lymphoma and autoimmune disease arguing that deregulation of PCD genes plays a role in disease development. Therefore, further understanding of bcl-x should provide ways to manipulate the cell death mechanism and ultimately to develop novel therapeutic strategies for cancer, autoimmune, and degenerative diseases.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA064556-04
Application #
2429815
Study Section
Pathology B Study Section (PTHB)
Project Start
1994-08-01
Project End
1999-05-31
Budget Start
1997-06-09
Budget End
1998-05-31
Support Year
4
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Pathology
Type
Schools of Medicine
DUNS #
791277940
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Dowds, Theresa A; Masumoto, Junya; Zhu, Li et al. (2004) Cryopyrin-induced interleukin 1beta secretion in monocytic cells: enhanced activity of disease-associated mutants and requirement for ASC. J Biol Chem 279:21924-8
Dowds, Theresa A; Masumoto, Junya; Chen, Felicia F et al. (2003) Regulation of cryopyrin/Pypaf1 signaling by pyrin, the familial Mediterranean fever gene product. Biochem Biophys Res Commun 302:575-80
Masumoto, Junya; Dowds, Theresa A; Schaner, Philip et al. (2003) ASC is an activating adaptor for NF-kappa B and caspase-8-dependent apoptosis. Biochem Biophys Res Commun 303:69-73
Masumoto, Junya; Zhou, Weibin; Chen, Felicia F et al. (2003) Caspy, a zebrafish caspase, activated by ASC oligomerization is required for pharyngeal arch development. J Biol Chem 278:4268-76
Inohara, Naohiro; Ogura, Yasunori; Nunez, Gabriel (2002) Nods: a family of cytosolic proteins that regulate the host response to pathogens. Curr Opin Microbiol 5:76-80
Liu, J Rebecca; Opipari, Anthony W; Tan, Lijun et al. (2002) Dysfunctional apoptosome activation in ovarian cancer: implications for chemoresistance. Cancer Res 62:924-31
Ogura, Y; Inohara, N; Benito, A et al. (2001) Nod2, a Nod1/Apaf-1 family member that is restricted to monocytes and activates NF-kappaB. J Biol Chem 276:4812-8
Inohara, N; Ogura, Y; Chen, F F et al. (2001) Human Nod1 confers responsiveness to bacterial lipopolysaccharides. J Biol Chem 276:2551-4
Inohara, N; Nunez, G (2001) The NOD: a signaling module that regulates apoptosis and host defense against pathogens. Oncogene 20:6473-81
del Peso, L; Gonzalez, V M; Inohara, N et al. (2000) Disruption of the CED-9.CED-4 complex by EGL-1 is a critical step for programmed cell death in Caenorhabditis elegans. J Biol Chem 275:27205-11

Showing the most recent 10 out of 48 publications