BAC-mediated transgenic expression of fluorescent autophagic protein Beclin 1 reveals a role for Beclin 1 in lymphocyte development.

Journal article

Beclin 1/Atg6 is an essential component of the evolutionary conserved PtdIns(3)-kinase (Vps34) protein complex that regulates macroautophagy (autophagy) in eukaryotic cells and also interacts with antiapoptotic Bcl-2 family members, Bcl-2, and Bcl-x(L). To elucidate the physiological function of Beclin 1, we generated transgenic mice producing a green fluorescent Beclin 1 protein (Beclin 1-GFP) under Beclin 1 endogenous regulation. The beclin 1-GFP transgene is functional because it completely rescues early embryonic lethality in beclin 1-deficient mice. The transgenic mice appear normal, with undetected change in basal autophagy levels in different tissues, despite the additional expression of functional Beclin 1-GFP. Staining of Beclin 1-GFP shows mostly diffuse cytoplasmic distribution in various tissues. Detailed analysis of the transgene expression by flow cytometry reveals a Bcl-2-like biphasic expression pattern in developing T and B cells, as well as differential regulation of expression in mature versus immature thymocytes following in vitro stimulation. Moreover, thymocytes expressing high Beclin 1-GFP levels appear increasingly sensitive to glucocorticoid-induced apoptosis in vitro. Our results, therefore, support a role for Beclin 1 in lymphocyte development involving cross talk between autophagy and apoptosis.

Authors: Arsov, I; Li, X; Matthews, G; Coradin, J; Hartmann, B

• Publication status: Published
• Journal: Cell death and differentiation
• Volume: 15
• Issue: 9
• Pages: 1385-1395
• Publication date: 2008-09-01
• DOI: 10.1038/cdd.2008.59
• EISSN: 1476-5403
• ISSN: 1350-9047
• Language: English
• Keywords: Mice; Thymus Gland; Apoptosis; Lymphocyte Activation; Glucocorticoids; Autophagy; Mice, Transgenic; Green Fluorescent Proteins; Dexamethasone; Apoptosis Regulatory Proteins; Proteins; Animals; B-Lymphocytes; T-Lymphocytes; CD4-Positive T-Lymphocytes; Fluorescent Dyes; Chromosomes, Artificial, Bacterial