世界秋海棠属侧膜组植物新资料

记述了秋海棠属侧膜组11新种,即星果草叶秋海棠(BegoniaasteropyrifoliaY.M.ShuietW.H.Chen)、耳托秋海棠(B.auritistipulaY.M.ShuietW.H.Chen)、桂南秋海棠(B.austroguangxiensisY.M.ShuietW.H.Chen)、水晶秋海棠(B.crystallinaY.M.ShuietW.H.Chen)、须苞秋海棠(B.fimbribracteataY.M.ShuietW.H.Chen)、巨叶秋海棠(B.gigaphyllaY.M.ShuietW.H.Chen)、黄氏秋海棠(B.huangiiY.M.ShuietW.H.Chen)、长柱秋海棠(B.longistylaY.M.ShuietW.H.Chen)、扁果秋海棠(B.platycarpaY.M.ShuietW.H.Chen)、喙果秋海棠(B.rhynchocarpaY.M.ShuietW.H.Chen)、多变秋海棠(B.variifoliaY.M.ShuietW.H.Chen);并报道了3新变种及1新名称,即疏毛越南秋海棠(B.boniiGagnep.var.remotisetulosaY.M.ShuietW.H.Chen)、密毛龙州秋海棠(B.morseiIrmsch.var.myriotrichaY.M.ShuietW.H.Chen)、簇毛伞叶秋海棠(B.umbr-aculifoliaY.WanetB.N.Changvar.flocculosaY.M.ShuietW.H.Chen)及彩纹秋海棠(B.variegataY.M.ShuietW.H.Chen)。     

中国福建汉族14个YSNPs位点的研究

本研究对中国福建汉族的 80份DNA样品中的 14个YSNPs位点及YAP位点进行了基因分型。结果发现 ,14个YSNPs位点中除M7、M4 5、M10 3位点未发现变异外 ,其余M9、M5 0、M110、M15、M134、M12 2、M95、M89、M119、M111、M88等 11个YSNPs位点和YAP位点均有不同程度的变异。单体型分析结果显示 :在福建省汉族中共发现H1、H3、H4、H5、H6、H8、H9七种单体型 ,其频率分别为 2 2 .5 %、1. 3%、1. 3%、1 .3%、30. 0 %、2 8. 8%、15 .0 %.。     

Individual comparisons of the levels of (E)-3-methyl-2-hexenoic acid, an axillary odor-related compound, in Japanese

The (E)-3-methyl-2-hexenoic acid (E3M2H), an axillary odor-related compound, is known to occur in Caucasians. The aims of this study were to clarify whether E3M2H contributes to axillary odor in Asians and to quantify and compare individual levels of E3M2H. Quantitative determination of E3M2H was performed by means of gas chromatography-mass spectrometry of sweat extracted from the axillary areas of T-shirts worn for 24 h by Japanese subjects. The amount of E3M2H was 15.9-34.6 nmol/ml in six of 30 subjects. Our method succeeded in quantitative analysis of E3M2H from axillary sweat collected individually; we also showed that E3M2H could be detected in Asians. This is the first report in which the amount of E3M2H in axillary sweat was quantified on an individual basis and compared to reveal individual differences. The results of this study indicate that E3M2H might contribute to axillary malodor in Asians as well as Caucasians.     

Comparative proteome analysis of culture supernatant proteins of Mycobacterium tuberculosis H37Rv and H37Ra

To examine the virulence factors of Mycobacterium tuberculosis H37Rv, the proteome was used to characterize the differences in protein expression between virulent M. tuberculosis H37Rv and attenuated M. tuberculosis H37Ra. Two-dimensional gel electrophoresis was performed to separate culture supernatant proteins extracted from M. tuberculosis H37Rv and M. tuberculosis H37Ra. The protein spots of interest were identified by mass spectrometry, and then the genes encoding the identified proteins were cloned and sequenced. Comparison of silver-stained gels showed that three well-resolved protein spots were present in M. tuberculosis H37Rv but absent from M. tuberculosis H37Ra. Protein spot no. 1 was identified as Rv2346c. Protein spot no. 2 was identified as Rv2347c, Rv1197, Rv1038c, and Rv3620c, which shared significant homology and had the same peptide fingerprinting using tryptic digestion. No M. tuberculosis protein matched protein spot no. 3. Rv2346c, Rv2347c, Rv1038c, and Rv3620c of M. tuberculosis H37Rv were located on the M. tuberculosis H37Ra chromosome, and multiple mutations were observed in the corresponding areas of M. tuberculosis H37Ra. Codon 59 (CAG, Gln) of Rv2347c and Rv3620c was replaced by termination codon (TAG) in M. tuberculosis H37Ra, which probably terminated the polypeptide elongation. These results demonstrate the importance of studying the gene products of M. tuberculosis and show that subtle differences in isogenic mutant strains might play an important role in identifying the attenuating mutations.     

Highly conserved M2e and hemagglutinin epitope-based recombinant proteins induce protection against influenza virus infection

Highly pathogenic influenza viruses continue to cause serious threat to public health due to their pandemic potential, calling for an urgent need to develop effective, safe, convenient, and universal vaccines against influenza virus infection. In this study, we constructed two recombinant protein vaccines, 2H5M2e-2H7M2e-H5FP-H7FP (hereinafter M2e-FP-1) and 2H5M2e-H5FP-2H7M2e-H7FP (hereinafter M2e-FP-2), by respectively linking highly conserved sequences of two molecules of ectodomain of M2 (M2e) and one molecule of fusion peptide (FP) epitope of hemagglutinin (HA) of H5N1 and H7N9 influenza viruses in different orders. The Escherichia coli-expressed M2e-FP-1 and M2e-FP-2 proteins induced similarly high-titer M2e-FP-specific antibodies in the immunized mice. Importantly, both proteins were able to prevent lethal challenge of heterologous H1N1 influenza virus, with significantly reduced viral titers and alleviated pathological changes in the lungs, as well as increased body weight and complete survivals, in the challenge mice. Taken together, our study demonstrates that highly conserved M2e and FP epitope of HA of H5N1 and H7N9 influenza viruses can be used as important targets for development of safe and economical universal influenza vaccines, and that the position of H7N9 M2e and H5N1 HA epitope sequences in the vaccine components has no significant effects on the immunogenicity and efficacy of M2e-FP-based subunit vaccines.     

Nomenclatural novelties in the Apiaceae (Umbelliferae)

The revision of the family Apiaceae (Umbelliferae) for the Flora of China has demonstrated the need to formally publish the following 12 nomenclatural novelties: Acronema minus (M. F. Watson) M. F. Watson & Z. H. Pan, A. brevipedicellatum Z. H. Pan & M. F. Watson, Angelica sinensis var. wilsonii (H. Wolff) Z. H. Pan & M. F. Watson, Harrysmithia franchetii (M. Hiroe) M. L. Sheh, Heracleum candicans var. obtusifolium (Wall. ex DC.) F. T. Pu & M. F. Watson, Hydrocotyle hookeri ssp. chinensis (Dunn ex R. H. Shan & S. L. Liou) M. F. Watson & M. L. Sheh, H. hookeri ssp. handelii (H. Wolff) M. F. Watson & M. L. Sheh, Libanotis grubovii (V. M. Vinogradova) M. L. Sheh & M. F. Watson, Ligusticum likiangense (H. Wolff) F. T. Pu & M. F. Watson, L. nematophyllum (Pimenov & Kljuykov) F. T. Pu & M. F. Watson, L. nullivittatum (K. T. Fu) F. T. Pu & M. F. Watson, Pleurospermum bicolor (Franch.) C. Norman ex Z. H. Pan & M. F. Watson. In addition, a lectotype is designated for P. govanianum (DC.) Benth. ex C. B. Clarke var. bicolor Franch. (P. bicolor).     

A型流感病毒H5N1的M2离子通道稳定细胞株的建立

A型流感病毒H5N1的M2离子通道(H5M2)基因经优化后由人工合成,适合于哺乳动物细胞中表达.通过酶切克隆于pcDNA4质粒,并在HEK293细胞中建立稳定细胞株.Western blotting和免疫荧光证实H5M2在稳定细胞中只有在四环素诱导下才能表达,并经膜片钳证实在HEK293细胞中表达的H5M2具有H 通道活性,为M2离子通道功能的研究和M2离子通道阻断剂筛选方法的建立提供了参考.     

Fast atom bombardment and collisional activation mass spectrometry of retinyl phosphate mannose synthesized by liver membranes

Fast atom bombardment (FAB) and collisional activation dissociation (CAD) mass-analysed ion kinetic energy (MIKE) spectra have confirmed the structures of retinyl phosphate (Ret-P), retinyl phosphate mannose (Ret-P-Man) and guanosine 5'-diphospho-D-mannose (GDP-Man). Ret-P-Man was made in vitro while Ret-P and GDP-Man were chemically synthesized. Positive ion FAB mass spectrometry of Ret-P showed an observable short-lived spectrum with a mass ion at m/z 367 [M + H]+, and a major fragment ion at m/z 269 [M + H - H3PO4]+. Negative ion FAB mass spectrometry of Ret-P showed a strong stable spectrum with a parent ion at m/z 365 [M - H]-, a glycerol (G) adduct ion at m/z 457 [M - H + G]- and a dimer ion at m/z 731 [2M - H]-. GDP-Man showed an intense spectrum with parent ion at m/z 604 [M - H]- and cationized species at m/z 626 [M + Na - 2H]- and 648 [M + 2Na - 3H]-. Negative ion FAB mass spectrometry of Ret-P-Man showed a parent ion at m/z 527 [M - H]- and a fragment ion at m/z 259 [C6H12PO9]-. The CAD-MIKE spectra showed structurally significant fragment ions at m/z 442 and 361 for the [M - H]- ion of GDP-Man, and at m/z 509, 406, 364 and 241 for the [M - H]- ion of Ret-P-Man. FAB and CAD-MIKE spectra have been applied successfully to confirm the structure of Ret-P-Man made in vitro from Ret-P and GDP-Man.     

BUCHBESPRECHUNGEN

Book reviewed in this article:
J arman , M artha V.: Impala Social Behavior: Territory, Hierarchy, Mating and the Use of Space. "Fortschritte der Verhaltensforschung - Advances in Ethology", Beihefte Z. Tierpsychologie, H. 21.
Handbook of Sensory Physiology. Ed. Board: H. A utrum , R. J ung , W. R. L oewenstein , D. M. M ackay and H.-L. T eüber . Vol. 7. Part 6: Comparative Physiology and Evolution of Vision in Invertebrates. A. Invertebrate Photoreceptors. By H. A utrum , M. F. B ennet , B. D iehn , K. H amdorf , M. H eisenberg , M. J arvilehto , P. K unze , R. M enzel , W. H. M iller , A. W. S nyder , D. G. S tavenga and M. Y oshida . Ed. by H. A utrum . Berlin, Heidelberg, New York:
Leitfaden für das zoologische Praktikum. Begründet von W. K ükenthal . Überarbeitet von M. R enner . 18., überarb. Auflage.     

为《Flora of China》提供的伞形科新资料

在为编写《Flora of China》伞形科而进行的修订工作中,提出了11个新组合,即矮小丝瓣芹Acronema minus (M. F. Watson) M. F. Watson & Z. H. Pan, 短柄丝瓣芹A. brevipedicellatum Z. H. Pan & M. F. Watson, 川西当归Angelica sinensis var. wilsonii (H. Wolff) Z. H. Pan & M. F. Watson, 云南细裂芹Harrysmithia franchetii (M. Hiroe) M. L. Sheh, 钝叶独活Heracleum candicans var. obtusifolium (Wall. ex DC.) F. T. Pu & M. F. Watson, 中华天胡荽Hydrocotyle hookeri ssp. chinensis (Dunn ex R. H. Shan & S. L. Liou) M. F. Watson & M. L. Sheh, 普渡天胡荽H. hookeri ssp. handelii (H. Wolff) M. F. Watson & M. L. Sheh, 锐棱岩风Libanotis grubovii (V. M. Vinogradova) M. L. Sheh & M. F. Watson, 美脉藁本Ligusticum likiangense (H. Wolff) F. T. Pu & M. F. Watson和线叶藁本L. nematophyllum (Pimenov & Kljuykov) F. T. Pu & M. F. Watson, 无管藁本L. nullivittatum (K. T. Fu) F. T. Pu & M. F. Watson和二色棱子芹Pleurospermum bicolor (Franch.) C. Norman ex Z. H. Pan & M. F. Watson.; 发现了1个新种,即短柄丝瓣芹。此外,还为Pleurospermum govanianum var. bicolor Franch.指定了后选模式。     

中国及越南樟科润楠属植物一些种类的修订

报道了产自中国和越南的樟科润楠属的4个种的修订结果,即:MachiluslongipedicellataH.Lec.为M.yunnanensisH.Lec.的异名;M.thunbergiiSieb.etZucc.var.condorensisH.Lec.为M.lohuiensisS.Lee的异名,而其中被H.Liou误定的Poilane13161号则为M.cicatricosa;过去被中国学者误当作M.longipedicel-lata的西藏及云南中部至西北部的部份标本是广泛分布于喜马拉雅地区的M.duthieiKingexHook.f.。     

Distribution and homologies of subunits in the LDH isoenzyme pattern of urodeles.

1. The subunit distribution and homologies of LDH isoenzymes are investigated in the species Triturus vulgaris, cristatus, alpestris and helveticus, and Ambystoma mexicanum by means of immunoprecipitation and starch gel electrophoresis. 2. Fresh tissue extracts contain the following patterns: (a) Trit. vulgaris--Two isoenzymes: the M4 and H4 tetramers. No hybrid formation is observed between H and M subunits. (b) Trit. cristatus--Two isoenzymes: the M4 and H4 tetramers. Occasional hybrid formation between H and M subunits takes place. (c) Trit. alpestris--Six isoenzymes: the M4, H4, H3H', H2H'2, HH'3 and H'4 tetramers. No hybrid formation between the M and the H and H' subunits is detected. (d) Trit. helveticus--Six isoenzymes: the M4, H4, H3H', H2H'2, HH'3, and H'4 tetramers; the H' subunit is more positively charged than the M subunit, which leads to pattern reversal in heart and skeletal muscle tissues. No hybrid formation between the M and the H and H' subunits is observed. (e) Ambyst. mex.--Eleven isoenzymes in heart, eye and brain, six isoenzymes in all other tissues tested. The presence of two M subunits, which form hybrids with the H subunit in a restricted way, is suggested. 3. In tissue extracts of the tested species the tendency of all present LDH subunits to form hybrids with each other without restriction is increased after prolonged storage at 2 degrees C. 4. The most acidic of the major isoenzymes (LDH1) in Trit. vulgaris, cristatus and helveticus tends to split into a series of sub-bands which migrate faster to the anode than the original main band.     

Factors Influencing the Production of H and M Antigens by Histoplasma capsulatum: Development and Evaluation of a Shake Culture Procedure

Studies were undertaken to improve the production of histoplasmin for use in complement-fixation tests and in the determination of H and M antibodies. A shake culture method performed at 25 C was developed with a yeast-phase inoculum. Eight strains of Histoplasma were tested in three synthetic media to evaluate the effects of strain and medium on H and M antigen production. Intrastrain variation was negligible, and antigen production was reproducible. All of the strains produced H antigen; six strains produced both H and M antigens, and two produced only H antigen. The time of H and M antigen appearance varied with the medium; M antigen appearance was dependent upon the strain and medium used. Titers of M antigen appeared to be greater in stagnant culture.     

Requirement of gene fadD33 for the growth of Mycobacterium tuberculosis in a hepatocyte cell line

Gene fadD33 of Mycobacterium tuberculosis, one of the 36 homologues of gene fadD of Escherichia coli identified in the M. tuberculosis genome, predictively encodes an acyl-CoA synthase, an enzyme involved in fatty acids metabolism. The gene is underexpressed in the attenuated strain M. tuberculosis H37Ra relative to virulent H37Rv and plays a role in M. tuberculosis virulence in BALB/c mice by supporting mycobacterial replication in the liver. In the present paper, we investigated the role of fadD33 expression in bacterial growth within the hepatocyte cell line HepG2, as well as in human monocyte-derived THP-1 cells and peripheral blood mononuclear cells. M. tuberculosis H37Rv proved able to grow within HepG2 cells, while the intracellular replication of M. tuberculosis H37Ra was markedly impaired; complementation of strain H37Ra with gene fadD33 restored its replication to the levels of H37Rv. Moreover, disruption of gene fadD33 by allelic exchange mutagenesis reduced the intracellular growth of M. tuberculosis H37Rv, and complementation of the fadD33-disrupted mutant with gene fadD33 restored bacterial replication. Conversely, fadD33 expression proved unable to influence M. tuberculosis growth in human phagocytes, as fadD33-disrupted M. tuberculosis H37Rv mutant, as well as fadD33-complemented M. tuberculosis H37Ra, grew within THP-1 cells and peripheral monocytes basically at the same rates as parent H37Rv and H37Ra strains. The results of these experiments indicate that gene fadD33 expression confers growth advantage to M. tuberculosis in immortalized hepatocytes, but not in macrophages, thus emphasizing the importance of fadD33 in liver-specific replication of M. tuberculosis.     

Molecular weight determination of methyl esters of mycolic acids using thermospray mass spectrometry.

Methyl esters of normal fatty acids, corynomycolate and corynomycolenate were used as model compounds for thermospray mass spectrometric procedures for molecular weight determination of the related nocardial mycolic acids. By using ammonium acetate at the positive ion generator, in both cases, a family of ions was produced. The following members were found and corresponded to the adducts: (1) M + H; M + NH4 and M + H + NH4 for methyl esters of normal fatty acids, whereas M + H, M + 2H and M + H + NH4 were the adducts most frequently observed with methyl corynomycolates. The methyl esters of C40-C48 mycolic acids from Rhodococcus rhodochrous exhibited prominent peaks corresponding to adducts M + H + NH4 whereas those corresponding to M + 2H showed slightly lower intensities. The structure M + H had no significant representatives with this subclass of mycolic acids. A similar pattern was observed with methyl esters of C50-C54 mycolic acids from Nocardia asteroides GUH-2. Ion peaks C50-C54 representing adducts M + 2H and M + H + NH4 prevailed in the mass spectrum. In this case, the intensities of peaks corresponding to M + 2H were slightly higher than those of the M + H + NH4. Essentially three main species of nocardomycolic acids were detected: (1) monounsaturated C50:1, C52:1 and C54:1; (2) diunsaturated C50:2, C52:2 and C54:2 and (3) triunsaturated C52:3 and C54:3 mycolic acids. The most abundant mycolic acid was C52:2 followed in decreasing abundance by C52:1, C54:2, C50:2, C52:3 and C54:3 mycolic acids.     

Binding of IL-1 beta to alpha-macroglobulins and release by thioredoxin.

Human alpha 2-macroglobulin (H alpha 2M) is a major IL-1 beta binding plasma protein. The characteristics of the H alpha 2M IL-1 beta complex formation suggested, that cleavage of the internal thiol ester in other members of the alpha-macroglobulin family (alpha M) could enable these proteins to bind IL-1 beta. Characterization of optimal conditions for binding 125I IL-1 beta to H alpha 2M showed that H alpha 2M-IL-1 beta complex formation could be obtained over a pH range of 6.3 to 9 in the presence of some metal cations (i.e., Zn2+, Cd2+, Cu2+, Ni2+). Other divalent metal cations (i.e., Mn2+, Mg2+, Ca2+) were without effect. Time kinetic studies showed that binding of IL-1 beta to H alpha 2M was complete within 200 min and that H alpha 2M-IL-1 beta complexes became increasingly resistant to dissociation by boiling in SDS as a function of incubation time. Human pregnancy zone protein, rat alpha 1-, alpha 2-macroglobulin (R alpha 1M, R alpha 2M), all homologous with H alpha 2M, were tested for their ability to bind IL-1 beta. In each instance, alpha M-IL-1 beta complex formation was observed only after treatment of alpha M with methylamine, a primary amine that causes cleavage of the internal thiol ester in alpha M and the appearance of free thiol groups. Similarly, for each of these proteins, complex formation was increased several fold in the presence of Zn2+. Competition experiments using cytokines or proteins of similar molecular mass as IL-1 beta established that only unlabeled IL-1 beta was effective in inhibiting binding of 125I IL-1 beta to H"F" alpha 2M. Acylation of H"F" alpha 2M by diethylpyrocarbonate blocked the binding of IL-1 beta when analyzed by native PAGE. Deacylation of H"F" alpha 2M with hydroxylamine partially restored the binding capacity of H"F" alpha 2M further supporting the involvement of histidyl residues in the Zn2(+)-dependent binding of IL-1 beta. Reduced thioredoxin, but not its alkylated form, from Escherichia coli readily releases H"F" alpha 2M bound IL-1 beta under conditions that did not lead to reduction of disulfide bonds in H"F" alpha 2M. The action of thioredoxin also augmented IL-1-like activity in two independent bioassays suggesting that H"F" alpha 2M bound IL-1 beta is partially biologically inactive or latent. These results suggest that "activated" alpha M exert a modulating role for IL-1 beta by exposing specific binding sites, which are inaccessible in the native proteins.(ABSTRACT TRUNCATED AT 400 WORDS)     

Probe the function of histone lysine 36 methylation using histone H3 lysine 36 to methionine mutant transgene in mammalian cells

Chondroblastoma is a cartilaginous tumor that typically arises under 25 y of age (80%). Recent studies have identified a somatic and heterozygous mutation at the H3F3B gene in over 90% chondroblastoma cases, leading to a lysine 36 to methionine replacement (H3.3K36M). In human cells, H3F3B gene is one of 2 genes that encode identical H3.3 proteins. It is not known how H3.3K36M mutant proteins promote tumorigenesis. We and others have shown that, the levels of H3K36 di- and tri-methylation (H3K36me2/me3) are reduced dramatically in chondroblastomas and chondrocytes bearing the H3.3K36M mutation. Mechanistically, H3.3K36M mutant proteins inhibit enzymatic activity of some, but not all H3K36 methyltransferases. Chondrocytes harboring the same H3F3B mutation exhibited the cancer cell associated phenotypes. Here, we discuss the potential effects of H3.3K36M mutation on epigenomes including H3K36 and H3K27 methylation and cellular phenotypes. We suggest that H3.3K36M mutant proteins alter epigenomes of specific progenitor cells, which in turn lead to cellular transformation and tumorigenesis.     

Immunoelectron microscopy studies with a monoclonal antibody directed against a receptor recognition site epitope in human alpha 2-macroglobulin.

Alpha 2-Macroglobulin (alpha 2M) is a plasma proteinase inhibitor that binds up to 2 mole of proteinase per mole of inhibitor. Proteinase binding or reaction with small primary amines causes a major conformational change in alpha 2M. As a result of this conformational change, a new epitope recognized by monoclonal antibody 7H11D6 is exposed. The association of alpha 2M-proteinase or alpha 2M-methylamine with alpha 2M cellular receptors is prevented by 7H11D6. In this investigation, the binding of 7H11D6 to alpha 2M was studied by electron microscopy. 7H11D6 bound to alpha 2M-methylamine and alpha 2M-trypsin but not to native alpha 2M. The structure of alpha 2M after conformational change resembled the letter "H." 7H11D6 epitopes were identified near the apices of the four arms in the alpha 2M "H" structure. 7H11D6 that was adducted to colloidal gold (7HAu) retained the specificity of the free antibody (binding to alpha 2M-trypsin but not to native alpha 2M). alpha 2M conformational change intermediates prepared by sequential reaction with a protein crosslinker and trypsin also bound 7HAu. These results suggest that a complete alpha 2M conformational change is not necessary for 7H11D6 epitope exposure and may not be required for receptor recognition. 7HAu was used to isolate a preparation consisting primarily of binary alpha 2M-trypsin (1 mole trypsin per mole alpha 2M instead of 2). Structures resembling the letter "H" were most common; however, each field showed some atypical molecules with arms that were compacted instead of thin and elongated.(ABSTRACT TRUNCATED AT 250 WORDS)     

H9N2 virus-derived M1 protein promotes H5N6 virus release in mammalian cells: Mechanism of avian influenza virus inter-species infection in humans

H5N6 highly pathogenic avian influenza virus (HPAIV) clade 2.3.4.4 not only exhibits unprecedented intercontinental spread in poultry, but can also cause serious infection in humans, posing a public health threat. Phylogenetic analyses show that 40% (8/20) of H5N6 viruses that infected humans carried H9N2 virus-derived internal genes. However, the precise contribution of H9N2 virus-derived internal genes to H5N6 virus infection in humans is unclear. Here, we report on the functional contribution of the H9N2 virus-derived matrix protein 1 (M1) to enhanced H5N6 virus replication capacity in mammalian cells. Unlike H5N1 virus-derived M1 protein, H9N2 virus-derived M1 protein showed high binding affinity for H5N6 hemagglutinin (HA) protein and increased viral progeny particle release in different mammalian cell lines. Human host factor, G protein subunit beta 1 (GNB1), exhibited strong binding to H9N2 virus-derived M1 protein to facilitate M1 transport to budding sites at the cell membrane. GNB1 knockdown inhibited the interaction between H9N2 virus-derived M1 and HA protein, and reduced influenza virus-like particles (VLPs) release. Our findings indicate that H9N2 virus-derived M1 protein promotes avian H5N6 influenza virus release from mammalian, in particular human cells, which could be a major viral factor for H5N6 virus cross-species infection.     

M33 condenses chromatin through nuclear body formation and methylation of both histone H3 lysine 9 and lysine 27

Heterochromatin, a type of condensed DNA in eukaryotic cells, has two main categories: Constitutive heterochromatin, which contains H3K9 methylation, and facultative heterochromatin, which contains H3K27 methylation. Methylated H3K9 and H3K27 serve as docking sites for chromodomain-containing proteins that compact chromatin. M33 (also known as CBX2) is a chromodomain-containing protein that binds H3K27me3 and compacts chromatin in vitro. However, whether M33 mediates chromatin compaction in cellulo remains unknown. Here we show that M33 compacts chromatin into DAPI-intense heterochromatin domains in cells. The formation of these heterochromatin domains requires H3K27me3, which recruits M33 to form nuclear bodies. G9a and SUV39H1 are sequentially recruited into M33 nuclear bodies to create H3K9 methylated chromatin in a process that is independent of HP1α. Finally, M33 decreases progerin-induced nuclear envelope disruption caused by loss of heterochromatin. Our findings demonstrate that M33 mediates the formation of condensed chromatin by forming nuclear bodies containing both H3K27me3 and H3K9me3. Our model of M33-dependent chromatin condensation suggests H3K27 methylation corroborates with H3K9 methylation during the formation of facultative heterochromatin and provides the theoretical basis for developing novel therapies to treat heterochromatin-related diseases.