Molecular variation and evolution of the tyrosine kinase domains of insulin receptor IRa and IRb genes in Cyprinidae

The insulin receptor （IR） gene plays an important role in regulating cell growth, differentiation and development. In the present study, DNA sequences of insulin receptor genes, IRa and IRb, were amplified and sequenced from 37 representative species of the Cyprinidae and from five outgroup species from non-cyprinid Cypriniformes. Based on coding sequences （CDS） of tyro- sine kinase regions of IRa and IRb, molecular evolution and phylogenetic relationships were analyzed to better understand the characteristics of IR gene divergence in the family Cyprinidae. 1Ra and IRb were clustered into one lineage in the gene tree of the IR gene family, reconstructed using the unweighted pair group method with arithmetic mean （UPGMA）. IRa and IRb have evolved into distinct genes after IR gene duplication in Cyprinidae. For each gene, molecular evolution analyses showed that there was no significant difference among different groups in the reconstructed maximum parsimony （MP） tree of Cyprinidae; IRa and 1Rb have been subjected to similar evolutionary pressure among different lineages. Although the amino acid sequences of IRa and IRb tyrosine kinase regions were highly conserved, our analyses showed that there were clear sequence variations between the tyrosine kinase regions of IRa and IRb proteins. This indicates that IRa and IRb proteins might play different roles in the insulin signaling pathway.

Identification of Fusarium wilt resistance gene SiRLK1 in Sesamum indicum L.

Sesame Fusarium wilt(SFW),caused by Fusarium oxysporum f.sp.sesami(Fos),is one of the most devastating diseases affecting sesame cultivation.Deciphering the genetic control of SFW resistance is pivotal for effective disease management in sesame.An inheritance study on a cross between the highly resistant variety Yuzhi 11 and the highly susceptible accession Sp1 using a Fos pathogenicity group 1 isolate indicated that resistance was conferred by a single dominant allele.The target locus was located in a 1.24 Mb interval on chromosome 3 using a combination of cross-population association mapping and bulked segregant analysis.Fine genetic mapping further narrowed the interval between 21,350 and 21,401 kb.The locus Sindi_0812400 was identified as the SFW resistance gene and officially designated SiRLK1.This gene encodes a specific malectin/receptor-like protein kinase with three putative tandem kinase domains and is considered a kinase fusion protein.Sequence analysis revealed that a high proportion(49.44%)of variants within the locus was located within the kinase domainⅢ,and several of which were evidently associated with the diversity in SFW response,indicating the critical role of kinase domainⅢin expression of disease resistance.These findings provide valuable information for further functional analysis of SFW resistance genes and marker-assisted resistance breeding in sesame.

Effect of Lysophosphatidylcholine on ATP and ρ-Nitrophenyl Phosphate Hydrolysis by the Plasma Membrane H^+-ATPase from Soybean Hypocotyls

The stimulatory effect of lysophosphatidylcholine (lyso_PC) on ATP and ρ_nitrophenyl phosphate (PNPP) hydrolysis by the plasma membrane H +_ATPase from soybean (Glycine max (L.) Merr.) hypocotyls was studied. Results showed that lyso_PC stimulated the hydrolysis of ATP; ATP hydrolysis was enhanced dramatically when lyso_PC was within 0-0.03%, and increased slightly when lyso_PC was higher than 0.03%. At the concentration of 0.03%, lyso_PC stimulated ATP hydrolysis by 80.5%. Kinetics analysis showed that V max increased from 0.46 μmol P i·mg -1 protein·min -1 to 0.87 μmol P i·mg -1 protein·min -1 while K m increased from 0.88 mmol/L to 1.15 mmol/L under lyso_PC treatment. The optimum pH of ATP hydrolysis was shifted from 6.5 to 7.0 . Moreover, it was found lyso_PC enhanced the inhibition of ATP hydrolysis by hydroxylamine. In the presence of 200 mmol/L hydroxylamine, ATP hydrolysis was inhibited by 74.4%, while it was inhibited by 84.4% when treated with lyso_PC. However, PNPP hydrolysis and the inhibitory effect of vanadate were not affected by lyso_PC. The above results indicated that the kinase domain might be an action site or regulatory region of the C_terminal autoinhibitory domain in the plant plasma membrane H +_ATPase.

Antibiotic and glucocorticoid-induced recapitulated hematological remission in acute myeloid leukemia:A case report and review of literature

BACKGROUND Leukemic hematopoietic cells acquire enhanced self-renewal capacity and impaired differentiation.The emergence of symptomatic leukemia also requires the acquisition of a clonal proliferative advantage.Untreated leukemia patients usually experience an aggressive process.However,spontaneous remission occasionally occurs in patients with acute myeloid leukemia(AML),most frequently after recovery from a febrile episode,and this is generally attributed to the triggering of antineoplastic immunity.There may be another explanation for the spontaneous remission as implicated in this paper.CASE SUMMARY A 63-year-old Chinese man presented with high fever,abdominal pain and urticaria-like skin lesions.He was diagnosed with AML-M4 with t(8;21)(q22;q22)/RUNX1-RUNX1T1 based on morphological,immunological,cytogenetic and molecular analyses.He had a complex chromosome rearrangement of 48,XY,t(8;21)(q22;q22),+13,+13[9]/49,idem,+mar[9]/49,idem,+8[2].He also had a mutated tyrosine kinase domain in fms-like tyrosine kinase 3 gene.He was treated with antibiotics and glucocorticoids for gastrointestinal infection and urticaria-like skin lesions.The infection and skin lesions were quickly resolved.Unexpectedly,he achieved hematological remission along with resolution of the febrile episode,gastrointestinal symptoms and skin lesions.Notably,after relapse,repeating these treatments resulted in a return to hematological remission.Unfortunately,he demonstrated strong resistance to antibiotic and glucocorticoid treatment after the second relapse and died of sepsis from bacterial infection with multidrug resistance.The main clinical feature of this patient was that symptomatic AML emerged with flaring of the gut inflammatory disorder and it subsided after resolution of the inflammation.Learning from the present case raises the possibility that in a subgroup of AML patients,the proliferative advantage of leukemia cells may critically require the presence of inflammatory stresses.CONCLUSION Inflammatory stresses,most likely arising from gastrointestinal infection,may sustain the growth and survival advantage of leukemic cells.

Electrical stimulation upregulates angiopoietin-1/Tie-2 mRNA expression in a rat model of focal cerebral ischemia

Angiopoietin-1/tyrosine kinase with immunoglobulin and epidermal growth factor homology domains 2 （Tie-2） is a newly discovered signaling pathway of angiogenesis. Angiogenesis benefits recovery of neurological functions such as swallowing. In the present study, a rat model of dysphagia following stroke was induced by middle cerebral artery occlusion to investigate the influence of low frequency electrical stimulus with bidirectional square waves and triangular waves on angiopoietin-1/-13e-2 mRNA expression. Reverse transcription-polymerase chain reaction results showed that low frequency electrical stimulus significantly improved the neurological scores of the model rats, and increased angiopoietin-1/＇13e-2 mRNA expression. This demonstrates that low frequency electrical stimulation can ameliorate neurological function in rats with focal brain ischemia, potentially through regulation of angiopoietin-1/-13e-2 expression in the angiogenesis pathway.

IKKβ mediates homeostatic function in inflammation via competitively phosphorylating AMPK and IκBα

Inhibitor of nuclear factor kappa-B kinase subunit beta(IKKβ)is one of important kinases in inflammation to phosphorylate inhibitor of nuclear factor kappa-B(IκBα)and then activate nuclear factor kappa-B(NF-κB).Inhibition of IKKβhas been a therapeutic strategy for inflammatory and autoimmune diseases.Here we report that IKKβis constitutively activated in healthy donors and healthy Ikkβ^(C46A)(cysteine 46 mutated to alanine)knock-in mice although they possess intensive IKKβ-IκBα-NF-κB signaling activation.These indicate that IKKβactivation probably plays homeostatic role instead of causing inflammation.Compared to IkkβWTlittermates,lipopolysaccharides(LPS)could induce high mortality rate in Ikkβ^(C46A) mice which is correlated to breaking the homeostasis by intensively activating p-IκBα-NF-κB signaling and inhibiting phosphorylation of 5’adenosine monophosphate-activated protein kinase(p-AMPK)expression.We then demonstrated that IKKβkinase domain(KD)phosphorylates AMPKa1 via interacting with residues Thr183,Ser184,and Thr388,while IKKβhelix-loop-helix motifs is essential to phosphorylate IκBαaccording to the previous reports.Kinase assay further demonstrated that IKKβsimultaneously catalyzes phosphorylation of AMPK and IκBαto mediate homeostasis.Accordingly,activation of AMPK rather than inhibition of IKKβcould substantially rescue LPS-induced mortality in Ikkβ^(C46A) mice by rebuilding the homeostasis.We conclude that IKKβactivates AMPK to restrict inflammation and IKKβmediates homeostatic function in inflammation via competitively phosphorylating AMPK and IκBα.