Blood sugar has powerful effects on gene expression and participates in

Blood sugar has powerful effects on gene expression and participates in the fasted to fed transition of the liver. hyperacetylated and HNF4α was constitutively bound in low and high glucose. Treatment with 20 mM glucose increased recruitment of ChREBP additional HNF4α and RNA polymerase II. Glucose stimulated the phosphorylation of the C terminal domain name of RNA polymerase II with increased Ser5 phosphorylation near the transcription start site and increased Ser2 phosphorylation near the termination signal. LY294002 and LY303511 blocked the recruitment of RNA polymerase II to the L-PK gene reducing LIPO the rate of transcription. The results of the scholarly studies demonstrate fundamental information on the molecular mechanism of glucose activated gene expression. Keywords: L-type pyruvate kinase LY294002 LY303511 insulin-independent blood sugar signaling hepatocytes chromatin immunoprecipitation gene promoter Launch Through the fasted-to-fed changeover insulin and blood sugar function in concert to bring about a programmed modification of gene appearance in the liver organ. This phenotypic change includes a rise in glycolytic and lipogenic gene appearance and a reduction in gluconeogenic and ketogenic gene appearance [1]. Insulin is necessary for glucokinase appearance which is necessary for increased blood sugar signaling and uptake. By expressing glucokinase in the lack of insulin such as for example with an adenovirus you can separate the consequences of insulin and blood sugar on gene appearance [1 2 One gene that’s induced by elevated blood sugar flux in the lack of insulin is certainly L-type pyruvate kinase (L-PK) [2]. Blood sugar activates the L-PK gene by recruiting carbohydrate response component binding proteins (ChREBP). In the fasted condition cAMP-dependent proteins kinase phosphorylates ChREBP making it struggling to bind to DNA and sequestering it in the cytosol [3]. After meals rich in sugars the upsurge in blood sugar flux qualified prospects to a rise in X-5-P amounts which leads to elevated PP2A activity. This PP2A dephosphorylates and activates ChREBP resulting in elevated glycolytic and lipogenic gene appearance MP-470 [3] although information on this model have already been challenged [4; 5; 6]. In today’s research we searched for to even more totally describe the molecular information on the blood sugar response. Using real-time RT-PCR nuclear run-ons and chromatin immunoprecipitation we performed a detailed molecular analysis of the insulinin-dependent glucose response of the L-PK gene. Materials and Methods Cell Culture HL1C rat hepatoma cells [7] were maintained as previously described [8]. Cells were transduced with an adenovirus expressing glucokinase (Ad-GK [9]) (a gift from Dr. Christopher Newgard) and incubated for 24 h. The amount of Ad-GK required to facilitate a glucose response in the HL1C hepatomas was established empirically by a functional titration wherein the amount of Ad-GK that conferred MP-470 a 2 to 3 3 fold MP-470 increase in L-PK gene expression was determined. Primary hepatocytes were isolated by a perfusion method as previously described [10]. Reverse transcription-polymerase chain reaction (RT-PCR) analysis RNA was isolated from HL1C hepatoma cells and primary hepatocytes using Tri-Reagent (Molecular Research Center Cincinnati OH) according to the manufacturer’s instructions. RT-PCR was carried out using a SYBR green grasp mix (Bio-Rad Hercules CA) MP-470 in an Applied Biosystems Prism 7300 Real-Time PCR System as previously described [6]. Fold change in mRNA MP-470 expression was decided using the ΔΔcT method with all genes normalized to cyclophilin [11]. Chromatin immunoprecipitation Chromatin immunoprecipitation (ChIP) was performed as previously described [10]. The ChREBP antibody was purchased from Novus (Littleton CO.