Extrapolating from these validation rates we estimate that at least 90% of the 115 genes obtained by SACO are C/EBP target genes. transcription, brain == Introduction == Since their discovery the family of CCAAT/Enhancer Binding Proteins has grown to include six users (C/EBP, , , , and ) (Johnson et al., 1986). C/EBPs are known to regulate the transcription of genes important for metabolism, differentiation and inflammation (Croniger et al., 1998;Hanson, 1998;Lekstrom-Himes and Xanthopolulous, 1998;Poli, 1998;Ramji and Foka, 2002) and are themselves regulated at the level Piboserod of transcription (Niehof et al., 1997), translation (Calkhoven et al., 1994;Lincoln et al., Piboserod 1998) and post-translationally by multiple signaling pathways (Trautwein et al., 1993;Nakajima et al., 1993;Umayahara et al., 2002). C/EBPs share a highly conserved C-terminal basic amino acid-rich DNA binding and leucine zipper dimerization (bZIP) domain name. With the exception of the homologous C/EBP protein C/EBP (a.k.a. CHOP) (Ubeda, 1996), C/EBPs Piboserod recognize the same DNA binding sequence (Falvey et al., 1996;Osada, et al. 1996). The N-terminal activation domains of C/EBPs are significantly less conserved than the bZIP domain name, with alternate ribosomal access sites or alternate splicing of exons generating C/EBP isoforms with additional N-terminal diversity (Descombes and Schibler, 1991;Yamanaka et al., 1997). C/EBPs dimerize not only with each other but with other bZIP proteins and dimerization outside of the immediate family modifies both DNA acknowledgement andtrans-activation Piboserod (Vallejo et al., 1993;Hsu et al., 1994;Newman and Keating, 2003;Cai et al., 2008). The variety of DNA binding and activation domains made available through heterodimerization enables C/EBPs to interact with a broad range of DNA sequences, transcription factors, co-activators and chromatin remodeling complexes (Milos and Zaret, 1992;Falvey et al., 1996;Lee et al., 1997;Kowenz-Leutz and Leutz, 1999;Gutierrez et al., 2002; Niehof et al., 2004). These unique attributes presumably increase the quantity of genes that are regulated by C/EBPs and enable differential gene expression even when more than one C/EBPs family member is expressed within the same cell (Colangelo et al., 1998;Yamanaka et. al, 1998;Zhu et al., 2002). The most abundant C/EBPs in the brain are C/EBP, and , which are enriched in neurons and regulated by cAMP- and calcium-dependent signaling mechanisms (Sterneck and Rabbit Polyclonal to PRKY Johnson, 1998;Sterneck et al., 1998;Yukawa et al., 1998;Nadeau et al, 2005;Lein et al., 2007). C/EBPs have been implicated in the control of biological processes crucial to neuronal development and survival, including cell fate determination (Menard et al., 2002;Paquin et al., 2005), apoptosis (Marshall et al., 2003), the synthesis of trophic factors (Symes et al., 1995;Colengalo et al., 1998;Takeuchi et al., 2002;McCauslin et al., 2006), the response to trophic factors (Sterneck and Johnson, 1998;Calella et al., 2007) and responses to brain injury and ischemia (Bernaudin et al., 2002;Cortes-Canteli et al., 2002;Soga et al., 2003;Nadeau et al., 2005;Kapadia et al., 2006). C/EBPs also have functions in transcriptional programs underlying more complex brain functions, such as learning and memory (Taubenfeld et al., 2001a;Taubenfeld et al., 2001b;Chen et al., 2003) and the effects of electroconvulsive shock (Chen et al., 2004), methamphetamine (Thomas et al., 2004) and hallucinogens (Nichols and Sanders-Bush, 2004) on brain neurochemistry. One strategy to elucidate the underlying biology of these processes is to identify and annotate functionally related physiological targets for C/EBPs in Piboserod the brain (C/EBP target genes). Classical gene promoter analysis has yielded only a limited quantity of neuronal C/EBP target genes, including the rate-limiting enzyme in tetrahydrobiopterin biosynthesis, GTP cyclohydrolase I (GCH1) (Kapatos et al., 2000,Kapatos et al., 2007), the structural protein -tubulin (Gloster et al., 1994), the peptide neurotransmitter material P (Kageyama et al., 1991;Kovacs et al., 2006), the metabotrophic glutamate receptors 1 and 5 (Corti et al., 2003;Crepaldi et al., 2007), the trophic factors nerve growth factor and brain derived neurotrophic factor (Colangelo and Johnson, 1998;McCauslin et al., 2006; Callela et al., 2007), the developmentally regulated bHLH transcription factor Nex1/Math-2/NeuroD (Uittenbogaard et al., 2007) and the immediate- early genes c-fos, Egr1 and Egr2 (Metz and Ziff, 1991;Calella et al., 2007). C/EBP target gene discovery was recently accelerated, however, by a study that combined chromatin immunoprecipitation (ChIP) and DNA microarray technology (ChIP-chip) to identify new target genes regulating hepatic metabolism and cell proliferation (Friedman et al., 2004). The overall goal of the present study was to identify genes in the brain that are regulated by C/EBPs. To accomplish this we designed a two-step process in which C/EBP target genes were first recognized in the rat.
