High impact information on Daf2

• We demonstrate that during primary T cell activation, the absence of Daf on antigen-presenting cells (APCs) and on T cells enhances T cell proliferation and augments the induced frequency of effector cells [1].
• We show that cognate T cell-APC interactions are accompanied by rapid production of alternative pathway components and down-regulation of Daf expression [1].
• Decay-accelerating factor (Daf) dissociates C3/C5 convertases that assemble on host cells and thereby prevents complement activation on their surfaces [1].
• Chromosome localization studies mapped the mouse Daf genes to chromosome 1, where they segregated with the C4-binding protein (C4bp) gene [2].
• Molecular cloning of mouse decay accelerating factor (DAF; CD55) predicted two forms of the molecule, one transmembrane (TM) and the other glycosylphosphatidylinositol (GPI)-anchored; these are encoded by separate genes termed Daf-GPI and Daf-TM [3].

Anatomical context of Daf2

• Northern blot analysis indicated that rat GPI-DAF mRNA was present in all tissues examined except for liver, while rat TM-DAF mRNA was preferentially expressed in testis [4].
• Examination of the fetoplacental unit at the day 7.5 stage revealed that GPI-DAF but not the TM-DAF gene is expressed in the maternal decidua cells surrounding the trophoectoderm of the embryo [5].
• These findings suggest that although the TM-DAF gene is irrelevant on mouse blood cells, the two DAF genes may have different roles in germ cell development and/or mature sperm function [5].
• In this study, we transfected cDNA of mouse GPI-DAF or TM-DAF into Chinese hamster ovary (CHO) cells [6].
• The findings argue that local alternative pathway activation and surface Daf protein function respectively as a costimulator and a negative modulator of T cell immunity and explain previously reported observations linking complement to T cell function [1].

Other interactions of Daf2

• In mice, both GPI-anchored and transmembrane-anchored DAF proteins are produced, each of which can be derived from two different genes (Daf1 and Daf2) [7].

References