家蚕血细胞特异表达新基因Bm04862的鉴定及表达

通过家蚕组织芯片数据筛选得到家蚕血细胞特异表达基因Bm04862,并首次对该基因进行了克隆与鉴定。应用RACE技术获得该基因全长,并对其进行生物信息学分析。Bm4862基因开放阅读框819 bp,共编码273个氨基酸残基,预测其为跨膜蛋白;通过q RT-PCR技术对其时空表达情况进行分析;结果显示Bm04862基因在家蚕血细胞中特异高表达,并在4龄眠期和预蛹2 d时达到表达高峰;构建Bm04862真核表达载体,转染Sf9细胞分析其蛋白的亚细胞定位情况,结果表明其定位于细胞核膜和部分细胞质中。此外,用大肠杆菌刺激蚕体24 h后,Bm04862基因表达水平显著上调,表明大肠杆菌可以诱导该基因的表达,由此推测该基因可能参与家蚕的免疫应答。这为深入研究该基因在家蚕免疫反应中的功能提供了参考。     

Different Rates of LINE-1 (L1) Retrotransposon Amplification and Evolution in New World Monkeys

LINE-1 (L1) elements constitute the major family of retrotransposons in mammalian genomes. Here we report the first investigation of L1 evolution in New World monkeys (NWM). Two regions of the second open-reading frame were analyzed by two methods in three NWM species, the squirrel monkey (Saimiri sciureus), the tamarin (Saguinus oedipus), and the spider monkey (Ateles paniscus). Since these three species diverged, L1 has amplified in the Saimiri and Saguinus lineages but L1 activity seems to have been strongly reduced in the Ateles lineage. In addition, the active L1 lineage has evolved rapidly in Saimiri and Saguinus, generating species-specific subfamilies. In contrast, we found no evidence for a species-specific subfamily in Ateles, a result consistent with the low L1 activity in this species for the last ~25 My.     

Full-Length L1 Elements Have Arisen Recently in the Same 1-kb Region of the Gorilla and Human Genomes

New copies of the mammalian retrotransposon L1 arise in the germline at an undetermined rate. Each new L1 copy appears at a specific evolutionary time point that can be estimated by phylogenetic analysis. In humans, the active L1 sequence L1.2 resides at the genomic locus LRE1. Here we analyzed the region surrounding the LRE1 locus in humans and gorillas to determine the evolutionary history of the region and to estimate the age of L1.2. We found that the region was composed of an ancient L1, L1Hs-Lrg, which was significantly divergent from all other L1 sequences available in the databases. We also determined that L1.2 was absent from the gorilla genome and arose in humans after the divergence of gorilla and human lineages. In the gorilla LRE1 region, we discovered a different full-length L1 element, L1Gg-1, which was allelic and present at a high gene frequency in gorillas but absent from other primates. We determined the nucleotide sequence of L1Gg-1 and found that it was 98% identical to L1.2, suggesting a close relationship between active L1s in gorillas and humans. Received: 28 December 1997 / Accepted: 20 March 1998     

Structure of Bombyx mori chemosensory protein 1 in solution

Chemosensory Proteins (CSPs) represent a family of conserved proteins found in insects that may be involved in chemosensory functions. BmorCSP1 is expressed mainly in antennae and legs of the silkworm moth Bombyx mori and was cloned from antennal cDNA. Here we report the determination of the structure of Bombyx mori CSP1 (BmorCSP1) by NMR. The overall fold of BmorCSP1 is globular and comprises six alpha-helices. These helices span residues 10-14, 17-27, 35-49, 57-72, 75-85, and 92-100. The internal hydrophobic sides of the helices are formed mostly by leucine and isoleucine residues and, therefore, well suited to constitute a binding site for hydrophobic ligands.     

家蚕微孢子虫感染对家蚕海龟蛋白(Bmtutl)基因表达水平的影响

【目的】本研究旨在阐明家蚕微孢子虫Nosema bombycis感染不同时间对家蚕Bombyx mori幼虫不同组织中家蚕海龟蛋白(Bombyx Turtle, Bmtutl)基因表达水平的影响,为揭示家蚕微孢子虫的侵染机制奠定基础。【方法】利用生物信息学方法对家蚕海龟蛋白3种亚型Bmtutl-464, Bmtutl-519和Bmtutl-810的序列结构特征进行了分析;利用qPCR检测家蚕微孢子虫感染后12, 24, 48, 72, 96和120 h,家蚕幼虫中肠、血淋巴与脂肪体组织中Bmtutl-464, Bmtutl-519和Bmtutl-810基因表达水平的变化情况。【结果】家蚕海龟蛋白3种亚型的二级结构均主要由无规则卷曲、α螺旋、β转角和延伸链组成,其中无规则卷曲所占比例最高。但是PredictProtein分析发现,Bmtutl-464, Bmtutl-519和Bmtutl-810之间的蛋白/多核苷酸结合位点存在较大差异。qPCR结果表明,感染家蚕微孢子虫后,家蚕幼虫中肠、血淋巴与脂肪体组织中Bmtutl-464, Bmtutl-519和Bmtutl-810基因的整体表达处于被抑制状态,尤其在脂肪体中最为明显：Bmtutl-519和Bmtutl-810基因的表达在家蚕微孢子虫感染家蚕后的72 h开始受到显著抑制,特别是Bmtutl-519基因,其相对表达水平均不到对照的5.0%。【结论】家蚕海龟蛋白这3种亚型的序列结构特征存在较大差异,家蚕微孢子虫感染在一定程度抑制了家蚕幼虫中肠、血淋巴与脂肪体组织中Bmtutl-464, Bmtutl-519和Bmtutl-810基因尤其是Bmtutl-519的表达。结果说明,与其他两种家蚕海龟蛋白亚型相比,Bmtutl-519蛋白可能在家蚕微孢子虫侵染宿主的过程中起主要作用。     

家蚕Hox基因研究进展

Hox基因（homeobox genes）在昆虫躯体模式（body plan）的发育调控机制中扮演着重要角色,其表达具有严格的组织特异性和胚胎发育的程序性。家蚕Bombyx mori作为鳞翅目昆虫的代表,其Hox基因也陆续得到鉴定。在家蚕中存在一个拟复等位基因群--E群基因,其突变表型均与过剩斑纹和过剩附肢有关,这可能与Hox基因有着密切联系。家蚕全基因组测序完成后,发现其Hox基因簇中存在12个特有的homeobox基因（Bmshx1~Bmshx12）, 说明家蚕Hox基因可能具有独特的生物学意义。我们还利用家蚕基因芯片数据分析了Bmlab与Bmpb基因的组织表达特征。通过对家蚕Hox基因的研究,探索家蚕躯体模式建立机制,可望为解析其他鳞翅目昆虫的躯体模式的建立机制提供理论依据。本文就家蚕Hox基因的表达、功能及其与E群突变的关系等方面进行了综述。     

Molecular structure of a novel gypsy-Ty3-like retrotransposon (Kabuki) and nested retrotransposable elements on the W chromosome of the silkworm Bombyx mori

We previously characterized a female-specific randomly amplified polymorphic DNA (RAPD), designated W-Kabuki, derived from the W chromosome of the silkworm, Bombyx mori. To further analyze the W chromosome of B. mori, we obtained a lambda phage clone which contains the W-Kabuki RAPD sequence and sequenced the 18.1-kb DNA insert. We found that this DNA comprises a nested structure of at least seven elements; three retrotransposons, two retroposons, one functionally unknown insertion, and one Bombyx repetitive sequence. The non-LTR retrotransposon BMC1, the retroposon Bm1, a functionally unknown inserted DNA (FUI), and a copia-like LTR retrotransposon (Yokozuna) are themselves inserted into a novel gypsy-Ty3-like LTR retrotransposon, named Kabuki. Furthermore, this Kabuki element is itself inserted into another copy of Bm1. The BMC1 and Yokozuna elements inserted in the Kabuki sequence are intact. Moreover, the Kabuki element is largely intact. These results suggest that many retrotransposable elements have accumulated on the W chromosome, and these elements are expected to evolve more slowly than those on other chromosomes. Received: 7 October 1999 / Accepted: 14 April 2000     

芸香苷对家蚕谷胱甘肽-S-转移酶部分基因的诱导表达

谷胱甘肽-S-转移酶(glutathione-S-transferases, GSTs) 是对一种机体的解毒代谢起重要作用并可以被诱导的酶系。为了从分子水平上探究家蚕Bombyx mori GSTs 基因与植物次生物质芸香苷代谢的关系, 本实验采用双跟踪标定定量PCR (dual-spike-in qPCR)方法, 用 5×10^-1, 5×10^-2, 5×10^-3 ng/μL 3 个浓度芸香苷溶液处理家蚕5龄幼虫, 并对各组织中 GSTs Epsilon 家族不同基因的转录水平进行检测。结果显示, 浓度为 5×10^-2 ng/μL 的芸香苷溶液能诱导GSTs 基因的转录水平发生显著变化。在中肠中, BmGSTe1, BmGSTe2 和 BmGSTe6的诱导转录水平较高, 在诱导后24 h达到最大值; 在脂肪体中BmGSTe1, BmGSTe6和BmGSTe7的转录水平相对较高且分别在诱导后 2 h, 2 h和4 h 达到最大值; 而GSTs基因在马氏管中表达量均很低或者检测不到表达。与 5×10^-2 ng/μL 浓度相比, 5×10^-1 ng/μL 的芸香苷溶液诱导后各基因的转录水平上升的幅度较小并且达到峰值的时间不同, 而 5×10^-3 ng/μL 浓度的芸香苷溶液并不能使GSTs基因的诱导转录水平发生变化。结果提示, 家蚕 GSTs Epsilon 家族基因对芸香苷的代谢具有重要作用。     

Rapid evolution of a young L1 (LINE-1) clade in recently speciated rattus taxa

L1 elements are retrotransposons that have been replicating and evolving in mammalian genomes since before the mammalian radiation. Rattus norvegicus shares the young L1_mlvi2 clade only with its sister taxon, Rattus cf moluccarius. Here we compared the L1_mlvi2 clade in these recently diverged species and found that it evolved rapidly into closely related but distinct clades: the L1_mlvi2-rm clade (or subfamily), characterized here from R. cf moluccarius, and the L1_mlvi2-rn clade, originally described in R. norvegicus. In addition to other differences, these clades are distinguished by a cluster of amino acid replacement substitutions in ORF I. Both rat species contain the L1_mlvi2-rm clade, but the L1_mlvi2-rn clade is restricted to R. norvegicus. Therefore, the L1_mlvi2-rm clade arose prior to the divergence of R. norvegicus and R. cf moluccarius, and the L1_mlvi2-rn clade amplified after their divergence. The total number of L1_mlvi2-rm elements in R. cf moluccarius is about the same as the sum of the L1_mlvi2-rm and L1_mlvi2-rn elements in R. norvegicus. The possibility that L1 amplification is in some way limited so that the two clades compete for replicative supremacy as well as the implications of the other distinguishing characteristic of the L1_mlvi2-rn and L1_mlvi2-rm clades are discussed. Received: 6 November 1996 / Accepted: 12 April 1997     

A behavioural gynandromorph of Bombyx mori

ABSTRACT. The mating behaviour of experimentally produced gynandromorphs of the silkworm moth, Bombyx mori L., were observed. Of 232 gynandromorphs, thirty-two showed unusual bisexual behaviours. The bisexual behaviours were classified into four behavioural types: 'dual personality', 'schizophrenic', 'intersexual' and 'sequence-crossed'. The dual personality gynandromorphs behaved like a male at one time and like a female at another. The schizophrenics displayed male and female behaviours simultaneously in different parts of their body. The intersexuals showed a mixed type of male and female behaviours. The sequence-crossed animals performed the wrong sexual behaviour (e.g. female) in the context of one sex (e.g. male) when the behaviour of the other sex (i.e. male) would normally have been appropriate. These bisexual behaviours are discussed in terms of sensory and neural mechanisms.     

Organization and developmental timing of the Bombyx mori chorion gene clusters in strain C108

We have standardized the map of chorion structural gene clusters in Bombyx mori strain C108 by analyzing quantitative and qualitative chorion electrophoretic markers in recombinant progeny from four independent crosses. In all we assigned 22 markers to three gene clusters, representing about one-third of the total number of chorion genes: 2 to Ch 1, 9 to Ch 2, and 8 to Ch 3. Three additional markers belong either to Ch 7 or Ch 2. By referring to published chorion protein synthesis patterns, we show that the clusters are restricted in their developmental specificities: Ch 3 appears to be an early locus, carrying all of the mapped early markers (4) and half of the early middles (3/6), while Ch 1 and Ch 2 carry predominantly middle (4/5) and all late, Hc (6) markers, along with some early middle markers (3). We cite evidence to show that Ch 1 and Ch 2 compose the left and right halves of a single gene cluster, which we formally designate as Ch 1–2.     

家蚕浓核症病毒感染昆虫细胞系的电镜观察

本实验首次用中国株家蚕浓核症病毒感染三株昆虫细胞系:油桐尺蠖卵巢细胞系(BS-484)、甘兰夜蛾卵巢细胞系(NIAS—MB—19)和秋粘虫卵巢细胞系(IPLB—SF—21)。结果仅在BS—484细胞中观察到病毒感染引起的细胞病变效应。电镜观察发现在感染的BS—484中,细胞核明显膨大,其中核仁活性化,数目增多,同时还观察到核仁膨大和分裂现象。感染5—6天,可看到成熟病毒粒子于核内形成。在感染的细胞质中,线粒体肥大且失去脊,粗面内质网变成小泡体,其内积累大量核糖核蛋白体。许多细胞器空泡化或退化,细胞质中出现一些包含退化细胞器的大型自身吞噬体。     

一种家蚕类浓核病毒的组织病理学特征

本文从家蚕病蚕中分离到一种家蚕类浓核病毒（BmDNV-Like）,对它的组织病理学研究表明:该病毒首先寄生家蚕中肠柱状细胞,继而引起其细胞核的膨大和破裂;组织原位杂交结果表明该病毒既能在家蚕中肠柱状细胞中增殖,也能在中肠的杯形细胞中增殖,甚至在感染后期能在家蚕幼虫的大部分组织细胞中感染和增殖。     

家蚕抗核型多角体病分子标记筛选

对家蚕抗核型多角病毒病以不同的杂交方式,构建3种近等基因系,用RAPD技术筛选出抗病主基因连锁分子标记OPA-18700和感病连锁分子标记OPY-11400。同时在F2群体中验证了抗性分子标记的有效性。