Disease relevance of Bhlhb2

• To investigate the transcriptional regulatory region of this gene, SHARP-2/firefly luciferase reporter plasmids were transfected into hepatoma cells [1].

High impact information on Bhlhb2

• A positive clone that encodes a basic helix-loop-helix protein, enhancer of split- and hairy-related protein-2 (SHARP-2), was obtained [2].
• In primary cultured rat hepatocytes, insulin rapidly induced an accumulation of SHARP-2 mRNA even in the absence of glucose [2].
• Thus, we conclude that insulin induces the transcription of the rat SHARP-2 gene via a phosphoinositide 3-kinase pathway [2].
• Although wortmannin, LY294002, and actinomycin D blocked the increase in SHARP-2 mRNA levels by insulin, rapamycin, staurosporine, PD98059, okadaic acid, and 8-bromocyclic AMP had no effect [2].
• Here we report the identification of a novel subfamily of bHLH proteins, defined by two mammalian enhancer-of-split- and hairy-related proteins, termed SHARP-1 and SHARP-2 [3].

Biological context of Bhlhb2

• Based on these findings, we conclude that SHARP-2 is a potential repressor of PEPCK gene expression [4].
• The influence of the enhancer of split- and hairy-related protein-2 (SHARP-2) transcriptional repressor on the expression of rat phosphoenolpyruvate carboxykinase (PEPCK) gene was examined [4].
• Finally, when a SHARP-2 expression plasmid was transiently transfected with various reporter plasmids into MH1C1 cells, the promoter activity of a PEPCK reporter plasmid was specifically decreased [4].
• The transcriptional activity of SHARP-2 also was examined using transient DNA transfection experiments [5].

Anatomical context of Bhlhb2

• The adenovirus-mediated overexpression of SHARP-2 in H4IIE cells and primary cultured rat hepatocytes led to a decrease in the levels of PEPCK mRNA [4].
• Similarly, within 1 h after the administration of kalnic acid in vivo, SHARP-2 is induced in neurons throughout the rat cerebral cortex [6].
• Furthermore, transfection experiments with green fluorescence protein (GFP) expression vectors into primary cultured granulosa cells and MA-10 cells revealed that the entire coding sequence of SHARP-2 fused to the GFP is localized in the nucleus [5].
• An in situ hybridization analysis showed that eCG treatment increases the level of the SHARP-2 transcript in theca interna cells and that hCG treatment, after the administration of eCG, increases the level of the SHARP-2 transcript in granulosa cells [5].

Associations of Bhlhb2 with chemical compounds

• When H4IIE cells were treated with epigallocatechin gallate, a green tea constituent, an increase in SHARP-2 mRNA levels and a decrease in PEPCK mRNA levels were observed [4].
• Similarly, within 1 h after the administration of kainic acid in vivo, SHARP-2 is induced in neurons throughout the rat cerebral cortex [3].

Other interactions of Bhlhb2

• When an expression vector encoding the full length of SHARP-2 was cotransfected with thymidine kinase promoter-luciferase reporter plasmids, with or without E box sequences, into MA-10 cells, the luciferase activity was decreased in an E box-dependent manner [5].

Analytical, diagnostic and therapeutic context of Bhlhb2

• Northern blot analysis revealed that the levels of SHARP-2 mRNA increase when a high carbohydrate diet is fed to normal rats or when insulin is administered to diabetic rats [2].

References