Dimerization and phosphorylation of thyrotropin-releasing hormone receptors are modulated by agonist stimulation

Dimerization and phosphorylation of thyrotropin-releasing hormone (TRH) receptors was characterized using HEK293 and pituitary GHFT cells expressing epitope-tagged receptors. TRH receptors tagged with FLAG and hemagglutinin epitopes were co-precipitated only if they were co-expressed, and 10-30% of receptors were isolated as hemagglutinin/FLAG-receptor dimers under basal conditions. The abundance of receptor dimers was increased when cells had been stimulated by TRH, indicating that TRH either stabilizes pre-existing dimers or increases dimer formation. TRH increased receptor dimerization and phosphorylation within 1 min in a dose-dependent manner. TRH increased phosphorylation of both receptor monomers and dimers, documented by incorporation of (32)P and an upshift in receptor mobility reversed by phosphatase treatment. The ability of TRH to increase receptor phosphorylation and dimerization did not depend on signal transduction, because it was not inhibited by the phospholipase C inhibitor. Receptor phosphorylation required an agonist but was not blocked by the casein kinase II inhibitor apigenin, the protein kinase C inhibitor GF109203X, or expression of a dominant negative form of G protein-coupled receptor kinase 2. TRH receptors lacking most of the cytoplasmic carboxyl terminus formed dimers constitutively but failed to undergo agonist-induced dimerization and phosphorylation. TRH also increased phosphorylation and dimerization of TRH receptors expressed in GHFT pre-lactotroph cells.     

Construction of a high density integrated genetic map for cucumber (Cucumis sativus L.)

The high-density consensus map was constructed based on the GY14 × PI 183967 map from an inter-subspecific cross and the extended S94 × S06 map from an intra-subspecific cross. The consensus map was composed of 1,369 loci, including 1,152 SSR loci, 192 SRAP loci, 21 SCAR loci and one STS locus as well as three gene loci of fruit external quality traits in seven chromosomes, and spanned 700.5 cM, of which 682.7 cM (97.5%) were covered by SSR markers. The average genetic distance and physical interval between loci were 0.51 cM and ~268 kbp, respectively. Additionally, the physical position of the sequence-associated markers aligned along the assembled cucumber genome sequence established a relationship between genetic maps and cucumber genome sequence and to a great extent validated the order of markers in individual maps and consensus map. This consensus map with a high marker density and well-ordered markers is a saturated and reliable linkage map for genetic analysis of cucumber or the Cucurbitaceae family of plants.     

Metabolic control analysis is helpful for informed genetic manipulation of oilseed rape (Brassica napus) to increase seed oil content

Top-down control analysis (TDCA) is a useful tool for quantifying constraints on metabolic pathways that might be overcome by biotechnological approaches. Previous studies on lipid accumulation in oilseed rape have suggested that diacylglycerol acyltransferase (DGAT), which catalyses the final step in seed oil biosynthesis, might be an effective target for enhancing seed oil content. Here, increased seed oil content, increased DGAT activity, and reduced substrate:product ratio are demonstrated, as well as reduced flux control by complex lipid assembly, as determined by TDCA in Brassica napus (canola) lines which overexpress the gene encoding type-1 DGAT. Lines overexpressing DGAT1 also exhibited considerably enhanced seed oil content under drought conditions. These results support the use of TDCA in guiding the rational selection of molecular targets for oilseed modification. The most effective lines had a seed oil increase of 14%. Moreover, overexpression of DGAT1 under drought conditions reduced this environmental penalty on seed oil content.     

Local habitat condition rather than geographic distance determines the genetic structure of Tamarix chinensis populations in Yellow River Delta,China

Tree Genetics &; Genomes - To breed a new variety of coffee (Coffea arabica) requires approximately 25&;nbsp;years due to the long generation time (5–6&;nbsp;years) of this perennial...     

The complete mitochondrial genome of the wild silkworm moth, Actias selene

The complete mitochondrial genome (mitogenome) of Actias selene (Lepidoptera: Saturniidae) was determined to be 15,236 bp, including 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes and a control region. The arrangement of 13 PCGs was similar to that of other sequenced lepidopterans. The AT skew of the mitogenome of A. selene was slightly negative, indicating a higher number of T compared to A nucleotides. The nucleotide composition of the mitogenome of A. selene was also biased toward A+T nucleotides (78.91%). All PCGs were initiated by ATN codons, except for the gene encoding cytochrome c oxidase subunit 1 (cox1), which may be initiated by the TTAG, as observed in other lepidopterans. Three genes, including cox1, cox2, and nad5, had incomplete stop codons consisting of just a T. With an exception for trnS1(AGN), all the other tRNA genes displayed a typical clover-leaf structure of mitochondrial tRNA. The A+T-rich region of the mitogenome of A. selene was 339 bp in length, and contains several features common to the Lepidopteras, including non-repetitive sequences, a conserved structure combining the motif ATAGA and an 18-bp poly-T stretch and a poly-A element upstream of trnM gene. Phylogenetic analysis showed that A. selene was close to Saturniidae.     

大棚网纹甜瓜品种主要经济性状模糊综合评判

本文根据模糊数学的基本原理,对大棚栽培的13个网纹甜瓜品种,采用品质、产量和成熟期等11个经济性状,进行模糊综合评判．结果表明：Andes和Volga的综合经济性状较好;Earl’sSeine夏系I、Marchen、秋绿、Earl’s东海PF80,Heim,Earl’sSeine夏系Ⅱ、夏绿和Kyanaru次之;Bolero,JohnnyEarl’s和Earl’s东海S78较差．作者认为：Andes及Volga为大棚栽培的首选品种,其次选用Earl’sSeine夏系I、秋绿和Earl’s东海PF80等品种．     

Lateral Organ Boundaries Domain 19 (LBD19) negative regulate callus formation in Arabidopsis

Plant Cell, Tissue and Organ Culture (PCTOC) - Callus is a remarkable regeneration tissue. The genes correlated with root development can be involved in regulating callus development in higher...     

KSRP is critical in governing hepatic lipid metabolism through controlling Per2 expression

Hepatic lipid metabolism is controlled by integrated metabolic pathways. Excess accumulation of hepatic TG is a hallmark of nonalcoholic fatty liver disease, which is associated with obesity and insulin resistance. Here, we show that KH-type splicing regulatory protein (KSRP) ablation reduces hepatic TG levels and diet-induced hepatosteatosis. Expression of period 2 (Per2) is increased during the dark period, and circadian oscillations of several core clock genes are altered with a delayed phase in Ksrp^−/− livers. Diurnal expression of some lipid metabolism genes is also disturbed with reduced expression of genes involved in de novo lipogenesis. Using primary hepatocytes, we demonstrate that KSRP promotes decay of Per2 mRNA through an RNA-protein interaction and show that increased Per2 expression is responsible for the phase delay in cycling of several clock genes in the absence of KSRP. Similar to Ksrp^−/− livers, both expression of lipogenic genes and intracellular TG levels are also reduced in Ksrp^−/− hepatocytes due to increased Per2 expression. Using heterologous mRNA reporters, we show that the AU-rich element-containing 3′ untranslated region of Per2 is responsible for KSRP-dependent mRNA decay. These findings implicate that KSRP is an important regulator of circadian expression of lipid metabolism genes in the liver likely through controlling Per2 mRNA stability.