In this task, you are given an abstract of article. Your task is to generate title for this article. Preferred titles are under thirty words.

The TCR:CD3 complex transduces signals that are critical for optimal T cell development and adaptive immunity. In resting T cells, the CD3 cytoplasmic tail associates with the plasma membrane via a proximal basic-rich stretch (BRS). In this study, we show that mice lacking a functional CD3-BRS exhibited substantial reductions in thymic cellularity and limited CD4- CD8- double-negative (DN) 3 to DN4 thymocyte transition, because of enhanced DN4 TCR signaling resulting in increased cell death and TCR downregulation in all subsequent populations. Furthermore, positive, but not negative, T cell selection was affected in mice lacking a functional CD3-BRS, which led to limited peripheral T cell function and substantially reduced responsiveness to influenza infection. Collectively, these results indicate that membrane association of the CD3 signaling domain is required for optimal thymocyte development and peripheral T cell function.
Membrane association of the CD3 signaling domain is required for optimal T cell development and function.

Using a sensitive Northern blot hybridization technique, gene expression of superoxide dismutase (SOD), catalase, and glutathione peroxidase was studied in pancreatic islets and for comparison in various other mouse tissues (liver, kidney, brain, lung, skeletal muscle, heart muscle, adrenal gland, and pituitary gland). Gene expression of the antioxidant enzymes was usually in the range of +/- 50% of that in the liver. Only in pancreatic islets gene expression was substantially lower. The levels of the cytoplasmic Cu/Zn SOD and the mitochondrial Mn SOD gene expression were in the range of 30-40% of those in the liver. Glutathione peroxidase gene expression was 15%, and catalase gene expression was not at all detectable in pancreatic islets. These low levels of antioxidant enzyme gene expression may provide an explanation for the extraordinary sensitivity of pancreatic beta cells towards cytotoxic damage by diabetogenic compounds and during the development of human and animal diabetes.
Low antioxidant enzyme gene expression in pancreatic islets compared with various other mouse tissues.

We targeted the locus encoding the cyclin-dependent kinase 2 (CDK2) by homologous recombination in mouse embryonic stem (ES) cells. Embryonic fibroblasts lacking CDK2 proliferate normally and become immortal after continuous passage in culture. Elimination of a conditional Cdk2 allele in immortal cells does not have a significant effect on proliferation. Cdk2/ mice are viable and survive for up to two years, indicating that CDK2 is also dispensable for proliferation and survival of most cell types. But CDK2 is essential for completion of prophase I during meiotic cell division in male and female germ cells, an unforeseen role for this cell cycle kinase.
Cyclin-dependent kinase 2 is essential for meiosis but not for mitotic cell division in mice