ABSTRACT
LEAFY/FLORICAULA (LFY/FLO) is a family of plant-specific transcription factors, which plays an important role(s) in the regulation of floral organ formation and development. So far, LFY regulation on floral development in wild soybean has not been reported in the literature. In this study, the LFY gene, GsLFY, has been isolated from Glycine soja, and characterized with molecular and transgenic techniques. The cDNA for GsLFY gene is 1224 bp in length and contains an open reading frame encoding a polypeptide of 407 amino acids. Quantitative RT-PCR analysis shows that GsLFY is prominently expressed in various tissues, including roots, flowers and seeds. Among the four floral organs, GsLFY is expressed highly in sepals and stamens while weakly in the petals and carpels. Yeast two-hybrid experiments show that GsLFY possesses transactivation activity while transient expression analysis with Arabidopsis thaliana protoplasts shows that GsLFY protein is localized in the nucleus, supporting the notion that GsLFY is a transcription factor. The GsLFY transgenic tobacco plants flower about 29 days earlier than the wild-type plants, thereby providing a potential rationale for developing new soybean varieties with altered flowering time.
Subject(s)
Fabaceae/genetics , Flowers/genetics , Genes, Plant/genetics , Plant Proteins/genetics , Amino Acid Sequence , Sequence AlignmentABSTRACT
This study aimed to investigate the effect of baclofen, a γ-aminobutyric acid B (GABAB) receptor agonist, on the expression of p-CREB and NR2B in the spinal dorsal horn of rats with diabetic neuropathic pain (DNP). The DNP rats, which were successfully induced with streptozocin, were distributed among 3 groups that were treated with saline (D1 group), baclofen (D2 group), or CGP55845 + baclofen (D3 group) continuously for 4 days. The rats induced with saline and subsequently treated with saline were used as controls (C group). The times for the paw withdrawal threshold and thermal withdrawal latency of the D1 group were lower than those for the C group, and were significantly increased after baclofen treatment, but not when GABA receptor was pre-blocked with CGP55845 (D3 group). Increased protein expression levels of NR2B and p-CREB and mRNA levels of NR2B were found in the D1 group when compared with the controls. Baclofen treatment significantly suppressed their expression, bringing it close to the levels of controls. However, in the D3 group, the expression of p-CREB and NR2B were still significantly higher than that of the controls. Activation of GABAB receptor by baclofen attenuates diabetic neuropathic pain, which may partly be accomplished via down-regulating the expression of p-CREB and NR2B.
Subject(s)
Baclofen/pharmacology , CREB-Binding Protein/metabolism , Diabetic Neuropathies/metabolism , GABA-B Receptor Agonists/pharmacology , Neuralgia/drug therapy , Receptors, N-Methyl-D-Aspartate/metabolism , Spinal Cord Dorsal Horn/drug effects , Animals , Baclofen/therapeutic use , CREB-Binding Protein/genetics , Diabetic Neuropathies/physiopathology , GABA-B Receptor Agonists/therapeutic use , GABA-B Receptor Antagonists/pharmacology , Gene Expression , Injections, Spinal , Male , Neuralgia/metabolism , Neuralgia/physiopathology , Pain Measurement , Rats, Sprague-Dawley , Receptors, N-Methyl-D-Aspartate/genetics , Spinal Cord Dorsal Horn/metabolismABSTRACT
N-methyl-D-aspartate receptor (NMDAR) activity is increased, while GABAB receptor is downregulated in the spinal cord dorsal horn in diabetic neuropathy. In this study, we determined the interaction of NMDARs and GABAB receptors in streptozotocin (STZ)-induced diabetic neuropathy. The paw withdrawal threshold (PWT) was significantly lower in STZ-treated rats than in vehicle-treated rats. Intrathecal injection of baclofen, a GABAB receptor agonist, significantly increased the PWT in STZ-treated rats, an effect that was abolished by pre-administration of the GABAB receptor specific antagonist CGP55845. Spinal NR2B, an NMDA receptor subunit, protein and mRNA expression levels were significantly higher in STZ-treated rats than in vehicle-treated rats. Intrathecal baclofen significantly reduced the NR2B protein and mRNA expression levels in STZ-treated rats. Intrathecal administration of CGP55845 eliminated baclofen-induced reduction of NR2B protein and mRNA levels in STZ-treated rats. In addition, the phosphorylated cAMP response element-binding (CREB) protein level was significantly higher in the spinal cord dorsal horn in STZ-treated rats compared with vehicle-treated rats. Intrathecal injection of baclofen significantly decreased phosphorylated CREB protein level in STZ-treated rats; an effect was blocked by CGP55845. These data suggest that activation of GABAB receptors in the spinal cord dorsal horn normalizes NMDAR expression level in diabetic neuropathic pain.