A novel microRNA regulates cooperation between symbiont and a laterally acquired gene in the regulation of pantothenate biosynthesis within Bemisia tabaci whiteflies.

Horizontally transferred genes (HTGs) play a key role in animal symbiosis, and some horizontally transferred genes or proteins are highly expressed in specialized host cells (bacteriocytes). However, it is not clear how HTGs are regulated, but microRNAs (miRNAs) are prime candidates given their previously demonstrated roles in symbiosis and impacts on the expression of host genes. A horizontally acquired PanBC that is highly expressed in whitefly bacteriocytes can cooperate with an obligate symbiont Portiera for pantothenate production, facilitating whitefly performance and Portiera titre. Here, we found that a whitefly miRNA, novel-m0780-5p, was up-regulated and its target panBC was down-regulated in Portiera-eliminated whiteflies. This miRNA was located in the cytoplasmic region of whitefly bacteriocytes. Injection of novel-m0780-5p agomir reduced the expression of PanBC in whitefly bacteriocytes, while injection of novel-m0780-5p antagomir enhanced PanBC expression. Agomir injection also reduced the pantothenate level, Portiera titre and whitefly performance. Supplementation with pantothenate restored Portiera titre and the fitness of agomir-injected whiteflies. Thus, we demonstrate that a whitefly miRNA regulates panBC-mediated host-symbiont collaboration required for pantothenate synthesis, benefiting the whitefly-Portiera symbiosis. Both panBC and novel-m0780-5p are present in the genomes of six Bemisia tabaci species. The expression of a novel miRNA in multiple B. tabaci species suggests that the miRNA evolved after panBC acquisition, and allowed this gene to be more tightly regulated. Our discovery provides the first account of a HTG being regulated by a miRNA from the host genome, and suggests key roles for interactions between miRNAs and HTGs in the functioning of symbiosis.

[Expression and Significance of Leucine-rich Repeat-containing G-protein Coupled Receptor 5/6 in Wnt Pathway in Children with Acute Lymphoblastic Leukemia].

Objective To study the expression and significance of leucine-rich repeat-containing G-protein coupled receptor(LGR)5/6 in childhood acute lymphoblastic leukemia(ALL). Methods A total of 39 children who had ALL and achieved complete remission on day 33 after induction therapy were enrolled.The children before induction therapy were considered as the incipient group,and those who achieved complete remission on day 33 by induction therapy were considered as the remission group.According to the degree of risk,they were assigned into 3 groups:low-risk(n=16),intermediate-risk(n=9),and high-risk(n=14)groups.A total of 30 children with immune thrombocytopenia were taken as the control group.From each child in the incipient group,remission group,and control group,3 ml bone marrow sample was collected.Real-time fluorescent quantitative polymerase chain reaction was conducted to measure the mRNA expression of LGR5 and LGR6 in the blood cells of bone marrow.Western blot was employed to measure the protein expression of LGR5 and LGR6 in blood cells of bone marrow. Results Compared with the control(mRNA:1.541±0.409,protein:0.138±0.041)and remission(mRNA:1.418±0.324,protein:0.130±0.033)groups,the incipient group had significantly lower mRNA(0.850±0.279)and protein(0.083±0.027)expression of LGR5(PmRNA=0.000,Pprotein=0.000).Compared with the control(mRNA:0.928±0.373,protein:0.094±0.037)and remission(mRNA:0.886±0.390,protein:0.111±0.039)groups,the incipient group had significantly higher mRNA(2.444±1.160)and protein(0.298±0.088)expression of LGR6(PmRNA=0.000,Pprotein=0.000).In the incipient groups,low-risk children showed significantly higher mRNA(1.004±0.284)and protein(0.097±0.030)expression of LGR5 than the intermediate-risk children(mRNA:0.728±0.239,protein:0.071±0.022)and high-risk children(mRNA:0.752±0.222,protein:0.074±0.020)(PmRNA=0.012,Pprotein=0.016);low-risk children showed significantly lower mRNA(1.822±0.979)and protein(0.245±0.077)expression of LGR6 than the intermediate-risk children(mRNA:2.954±1.039,protein:0.338±0.081)and high-risk children(mRNA:2.827±1.165,protein:0.333±0.075)(PmRNA=0.016,Pprotein=0.004).In the remission groups,low-risk children showed significantly higher mRNA(1.597±0.329)and protein(0.150±0.035)expression of LGR5 than the intermediate-risk children(mRNA:1.277±0.288,protein:0.117±0.029)and high-risk children(mRNA:1.305±0.253,protein:0.116±0.023)(PmRNA=0.012,Pprotein=0.006);low-risk children showed significantly lower mRNA(0.662±0.334)and protein(0.089±0.034)expression of LGR6 than the intermediate-risk children(mRNA:1.066±0.273,protein:0.130±0.033)and high-risk children(mRNA:1.027±0.405,protein:0.126±0.038)(PmRNA=0.007,Pprotein=0.007). Conclusion The expression of LGR5 and LGR6 are closely related to the occurrence and risk of childhood ALL,but its mechanism needs further study.

[Expression and Significance of Low-Density Lipoprotein-Related Receptors 5 and 6 in the Wnt/ß-Catenin Signaling Pathway in Childhood Acute Lymphoblastic Leukemia].

OBJECTIVE: To investigate the significance of low-density lipoprotein receptor-related protein 5 and 6 (LRP5/6) in the Wnt/ß-catenin signaling pathway in the pathogenesis and prognosis of childhood acute lymphoblastic leukemia (ALL). METHODS: A total of 43 children who were newly diagnosed and achieved complete remission after remission induction therapy were enrolled. The children before treatment were included in incipient group, and after treatment when achieved complete remission included in remission group. A total of 39 children with immune thrombocytopenia were enrolled in control group. Three milliliter bone marrow samples were collected from above-mentioned each group. QRT-PCR was used to determine the mRNA expression of LRP5 and LRP6 in blood mononuclear cells of bone marrow. Western blot was used to detect the protein expression of LRP5 and LRP6. According to the protein expression levels of LRP5 and LRP6, the children were divided into low-expression group and high-expression group, and the clinical biological characteristics were compared between these two groups. Survival analysis was performed by Kaplan-Meier method. RESULTS: Both mRNA and protein expression levels of LRP5 and 6 were upregulated in the incipient group compared with the control and remission group (P<0.05). The mRNA and protein expressions of LRP5 and LRP6 in the high-risk group were higher than those in the medium-risk group (P<0.05), it is the same as in the medium-risk group than the low-risk group (P<0.05). The mRNA and protein expressions of LRP5 and 6 positively correlated with risk degree in the incipient group (rLRP5 mRNA=0.84, P<0.05; rLRP6 mRNA=0.66, P<0.05; rLRP5 protein=0.82, P<0.05; rLRP6 protein=0.76, P<0.05). The white blood cell count and lactate dehydrogenase in LRP5 and LRP6 high expression group were significantly higher than those in low expression group (P<0.05), while there was no significant difference in other biological characteristics. Kaplan-meier survival analysis showed that in the 43 children 3-year overall survival rate and event-free survival rate was (91.7±4.7)% and (87.6±5.2)%, respectively. CONCLUSION: The high expression of LRP5/6 may be one of the pathogenesis of childhood ALL, and the degree of LRP5/6 increase may be related to the risk level.

Patterns of host cell inheritance in the bacterial symbiosis of whiteflies.

Whiteflies possess bacterial symbionts Candidatus Portiera aleyrodidium that are housed in specialized cells called bacteriocytes and are faithfully transmitted via the ovary to insect offspring. In one whitefly species studied previously, Bemisia tabaci MEAM1, transmission is mediated by somatic inheritance of bacteriocytes, with a single bacteriocyte transferred to each oocyte and persisting through embryogenesis to the next generation. Here, we investigate the mode of bacteriocyte transmission in two whitefly species, B. tabaci MED, the sister species of MEAM1, and the phylogenetically distant species Trialeurodes vaporariorum. Microsatellite analysis supported by microscopical studies demonstrates that B. tabaci MED bacteriocytes are genetically different from other somatic cells and persist through embryogenesis, as for MEAM1, but T. vaporariorum bacteriocytes are genetically identical to other somatic cells of the insect, likely mediated by the degradation of maternal bacteriocytes in the embryo. These two alternative modes of transmission provide a first demonstration among insect symbioses that the cellular processes underlying vertical transmission of bacterial symbionts can diversify among related host species associated with a single lineage of symbiotic bacteria.

Intracellular symbionts drive sex ratio in the whitefly by facilitating fertilization and provisioning of B vitamins.

Symbionts can regulate animal reproduction in multiple ways, but the underlying physiological and biochemical mechanisms remain largely unknown. The presence of multiple lineages of maternally inherited, intracellular symbionts (the primary and secondary symbionts) in terrestrial arthropods is widespread in nature. However, the biological, metabolic, and evolutionary role of co-resident secondary symbionts for hosts is poorly understood. The bacterial symbionts Hamiltonella and Arsenophonus have very high prevalence in two globally important pests, the whiteflies Bemisia tabaci and Trialeurodes vaporariorum, respectively. Both symbionts coexist with the primary symbiont Portiera in the same host cell (bacteriocyte) and are maternally transmitted. We found that elimination of both Hamiltonella and Arsenophonous by antibiotic treatment reduced the percentage of female offspring in whiteflies. Microsatellite genotyping and cytogenetic analysis revealed that symbiont deficiency inhibited fertilization in whiteflies, leading to more haploid males with one maternal allele, which is consistent with distorted sex ratio in whiteflies. Quantification of essential amino acids and B vitamins in whiteflies indicated that symbiont deficiency reduced B vitamin levels, and dietary B vitamin supplementation rescued fitness of whiteflies. This study, for the first time, conclusively demonstrates that these two intracellular symbionts affect sex ratios in their whitefly hosts by regulating fertilization and supplying B vitamins. Our results reveal that both symbionts have the convergent function of regulating reproduction in phylogenetically-distant whitefly species. The 100% frequency, the inability of whiteflies to develop normally without their symbiont, and rescue with B vitamins suggests that both symbionts may be better considered co-primary symbionts.