Multiple Mechanisms Activate Cd79a Transcription in Early B Cells

For many years, the B cell-specific Cd79a promoter has served as a useful model for defining requirements for gene activation in early progenitors, and thus, B lineage specification. When fully activated, the TATA-less promoter (localized to *200 base pairs) binds multiple lineage-restricted DNA-binding proteins including EBF1, Runx1(and its obligate partner CBFb), E2A proteins and Pax5, which recruits Ets family proteins to bind a composite site (Fig. 3) (Hagman et al. 1991 Travis et al. 1991...

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Runx1 J H3K9 methylation _) Runx3 I Hypothetical maturation enhancer E4m Runx1 J H3K9 methylation _) Runx3 I Hypothetical maturation enhancer E4m Cd4 silencing to continue past the DN stage (Naito et al. 2007). Taking into account that NuRD is generally considered a repressive chromatin remodeling complex, it is tempting to speculate that NuRD could remodel S4 chromatin to a state inaccessible to Runx1, eliminating silencer function during the transition from DN to DP. Taken together, it...

References

Akimzhanov AM, Yang XO, Dong C (2007) Chromatin remodeling of interleukin-17 (IL-17)-IL-17F cytokine gene locus during inflammatory helper T cell differentiation. J Biol Chem 282 5969-5972 Amsen D, Spilianakis CG, Flavell RA (2009) How are T(H)1 and T(H)2 effector cells made Curr Opin Immunol 21 153-160 Ansel KM, Lee DU, Rao A (2003) An epigenetic view of helper T cell differentiation. Nat Immunol 4 616-623 Ansel KM, Djuretic I, Tanasa B, Rao A (2006) Regulation of Th2 differentiation and Il4...

Epigenetic Regulation of the Cd8 Locus

The Cd8 locus consists of the Cd8a and Cd8b genes, separated by 35kb in mice, and 25kb in humans. CD8 is expressed either as a homo-dimer of CD8aa molecules, for example on intraepithelial lymphocytes IEL and CD8 DCs, or as a heterodimer of CD8ab molecules on DP thymocytes and TCRab cytotoxic T cells. Thus Cd8a and Cd8b genes can be both co-regulated and independently regulated reviewed in Taniuchi et al. 2004 . Here we focus mainly on Cd8 locus regulation in the TCRab lineage, and what hints...

Differential Regulation of Proximal and Distal VH Recombination

Recognition that proximal and distal VH genes are differentially regulated came from the observation that proximal VH genes recombined much more frequently than distal VH genes during fetal B cell ontogeny Yancopoulos et al. 1984 Perlmutter et al. 1985 Lawler et al. 1987 Jeong and Teale 1988 Malynn et al. 1990 ten Boekel et al. 1997 . Based on current information, the simplest explanation for this is that IL-7 IL-7R signaling pathway, which is important for distal VH recombination, is not a...