2A)
2A). transcription factor 3 (ATF3). In addition, treatment with Sox11 siRNAsin vitroandin vivocaused a transcriptional and translational level reduction in ATF3 expression. These anatomical and expression data support an intrinsic role for Sox11 in events that underlie successful regeneration following peripheral nerve injury. Keywords:Sensory neuron, RNA interference, Axotomy, Cutaneous nerve, Injury, Sry, Penetratin == 1. Introduction == The SRY-box made up of gene 11 (Sox11) transcription factor is a member of the group C high mobility group transcription factor A-804598 family, which also includes Sox4 and Sox12 (Azuma et al., 1999;Dy et al., 2008;Hargrave et al., 1997;Wright et al., 1993). Group C proteins are expressed throughout the developing nervous system and comprise one of seven sequence homology defined subgroups in the Sox family (Bergsland et al., 2006;Wegner and Stolt, 2005).Soxgene expression is regulated both spatially and temporally during development (Gubbay et al., 1990;Wilson and Koopman, 2002;Wright et al., 1993) and all appear to have critical functions in embryonic growth (Wegner and Stolt, 2005). Sox factors may activate or repress transcription of target genes and in many cases overlap in expression. For example, in developing mice both Sox11 and Sox4 are required for expression of the pan-neuronal geneTuj1(Bergsland et al., 2006). This overlap, coupled with embryonic or perinatal lethality in gene deletion models, has made detailed study of the functional functions of Sox factors challenging (Cheung et al., 2000;Sock et al., 2004). In addition to their role in development, some Sox proteins have been found to modulate adult A-804598 injury responses as well. For example, increased Sox18 expression in epithelial cells correlates with capillary sprouting after wounding (Darby et al., 2001). Similarly, Sox15 knockout mice display disrupted muscle mass regeneration (Meeson et al., 2007) and increased expression of Sox 5, 6 or 9 is usually important for healing of bone fractures (Uusitalo et al., 2001). Whether Sox11 has a comparable role in adult tissues has not been directly tested. Sox11 is expressed at high levels in developing sensory neurons and is hypothesized to regulate neuronal maturation (Hargrave et al., 1997). Its expression is significantly reduced during late phases of gestation and normally remains at low levels in adult neurons. A strong induction occurs however, in adult dorsal root sensory neurons following A-804598 axotomy (Jankowski et al., 2006;Tanabe et al., 2003), suggesting a regulatory role in nerve regeneration. In support of this possibility, cultured adult DRG neurons treated with Sox11 siRNAs exhibit a significant decrease in regeneration as indicated by reduced neurite length and branching index (Jankowski et al., 2006). Elements that regulate regeneration in the peripheral nervous system (PNS) following nerve injury are of CDC46 significant interest because, in contrast to the central nervous system, axon regeneration in the PNS can occur quite successfully (Cajal, 1928;Silver and Miller, 2004). Transcription factors such as c-Jun, a component of the AP-1 transcription factor complex, A-804598 and activated transcription factor 3 (ATF3), a member of the ATF/cAMP-responsive element binding protein (CREB) family, may underlie part of this dichotomy in A-804598 regenerative ability. Both genes are normally expressed at low levels in adult DRG neurons and rise significantly following peripheral axotomy (Lindwall et al., 2004;Tsujino et al., 2000;Raivich et al., 2004) or after dissociation and culture (Seijffers et al., 2006). For ATF3, the increase in expression is usually hypothesized to facilitate expression of survival and axon growth related genes (Lindwall and Kanje, 2005;Seijffers et al., 2006). Indeed, constitutive expression of a Thy-1.2 ATF3 transgene in neurons of transgenic mice enhanced PNS regeneration (Seijffers et al., 2007). Because Sox11 is usually similarly upregulated following axotomy, we tested its rolein vivousing a newly developed RNAi nerve injection delivery system. Results show that Sox11 has an important role in axon growth that may involve conversation with ATF3. == 2. Results == == 2.1. Sox11 expression in DRG neurons is usually increased in response to peripheral but.