Cellular motor protein KIF-4 associates with retroviral Gag.

Previously we demonstrated that murine retroviral Gag proteins associate with a cellular motor protein, KIF-4. Using the yeast two-hybrid assay, we also found an association of KIF-4 with Gag proteins of Mason-Pfizer monkey virus (MPMV), simian immunodeficiency virus (SIV), and human immunodeficiency virus type 1 (HIV-1). Studies performed with mammalian cell systems confirmed that the HIV-1 Gag protein associates with KIF-4. Soluble cytoplasmic proteins from cells infected with recombinant vaccinia virus expressing the entire Gag-Pol precursor protein of HIV-1 or transfected with HIV-1 molecular clone pNL4-3 were fractionated by sucrose gradient centrifugation and further separated by size-exclusion and anion-exchange chromatographies. KIF-4 and HIV-1 Gag cofractionated in both chromatographic separations. Immunoprecipitation assays have also verified the KIF-4-Gag association. KIF-4 binds mainly to the Gag precursor (Pr55 Gag) and a matrix-capsid processing intermediate (Pr42) but not to other processed Gag products. The binding of Gag is mediated by a domain of KIF-4 proximal to the C terminus. These results, and our previous studies, raise the possibility that KIF-4 may play an important role in retrovirus Gag protein transport

Binding of murine leukemia virus Gag polyproteins to KIF4, a microtubule-based motor protein.

A cDNA clone encoding a cellular protein that interacts with murine leukemia virus (MuLV) Gag proteins was isolated from a T-cell lymphoma library. The sequence of the clone is identical to the C terminus of a cellular protein, KIF4, a microtubule-associated motor protein that belongs to the kinesin superfamily. KIF4-MuLV Gag associations have been detected in vitro and in vivo in mammalian cells. We suggest that KIF4 could be involved in Gag polyprotein translocation from the cytoplasm to the cell membrane

Eef1a2 Promotes Cell Growth, Inhibits Apoptosis and Activates JAK/STAT and AKT Signaling in Mouse Plasmacytomas

The canonical function of EEF1A2, normally expressed only in muscle, brain, and heart, is in translational elongation, but recent studies suggest a non-canonical function as a proto-oncogene that is overexpressed in a variety of solid tumors including breast and ovary. Transcriptional profiling of a spectrum of primary mouse B cell lineage neoplasms showed that transcripts encoding EEF1A2 were uniquely overexpressed in plasmacytomas (PCT), tumors of mature plasma cells. Cases of human multiple myeloma expressed significantly higher levels of EEF1A2 transcripts than normal bone marrow plasma cells. High-level expression was also a feature of a subset of cell lines developed from mouse PCT and from the human MM.Heightened expression of EEF1A2 was not associated with increased copy number or coding sequence mutations. shRNA-mediated knockdown of Eef1a2 transcripts and protein was associated with growth inhibition due to delayed G1-S progression, and effects on apoptosis that were seen only under serum-starved conditions. Transcriptional profiles and western blot analyses of knockdown cells revealed impaired JAK/STAT and PI3K/AKT signaling suggesting their contributions to EEF1A2-mediated effects on PCT induction or progression.EEF1A2 may play contribute to the induction or progression of some PCT and a small percentage of MM. Eef1a2 could also prove to be a useful new marker for a subset of MM and, ultimately, a possible target for therapy

Diverse Hematological Malignancies Including Hodgkin-Like Lymphomas Develop in Chimeric MHC Class II Transgenic Mice

A chimeric HLA-DR4-H2-E (DR4) homozygous transgenic mouse line spontaneously develops diverse hematological malignancies with high frequency (70%). The majority of malignancies were distributed equally between T and B cell neoplasms and included lymphoblastic T cell lymphoma (LTCL), lymphoblastic B cell lymphoma (LBCL), diffuse large B cell lymphoma (DLBCL), the histiocyte/T cell rich variant of DLBCL (DLBCL-HA/T cell rich DLBCL), splenic marginal zone lymphoma (SMZL), follicular B cell lymphoma (FBL) and plasmacytoma (PCT). Most of these neoplasms were highly similar to human diseases. Also, some non-lymphoid malignancies such as acute myeloid leukemia (AML) and histiocytic sarcoma were found. Interestingly, composite lymphomas, including Hodgkin-like lymphomas, were also detected that had CD30+ Hodgkin/Reed-Sternberg (H/RS)-like cells, representing a tumor type not previously described in mice. Analysis of microdissected H/RS-like cells revealed their origin as germinal center B cells bearing somatic hypermutations and, in some instances, crippled mutations, as described for human Hodgkin lymphoma (HL). Transgene integration in an oncogene was excluded as an exclusive driving force of tumorigenesis and age-related lymphoma development suggests a multi-step process. Thus, this DR4 line is a useful model to investigate common molecular mechanisms that may contribute to important neoplastic diseases in man

Normalization of the Lymph Node T Cell Stromal Microenvironment in lpr/lpr Mice Is Associated with SU5416-Induced Reduction in Autoantibodies

The vascular-stromal elements of lymph nodes can play important roles in regulating the activities of the lymphocytes within. During model immune responses, the vascular-stromal compartment has been shown to undergo proliferative expansion and functional alterations. The state of the vascular-stromal compartment and the potential importance of this compartment in a spontaneous, chronic model of autoimmunity have not been well studied. Here, we characterize the vascular expansion in MRL-lpr/lpr lymph nodes and attempt to ask whether inhibiting this expansion can interfere with autoantibody generation. We show that characteristics of vascular expansion in enlarging MRL-lpr/lpr lymph nodes resemble that of the VEGF-dependent expansion that occurs in wild-type mice after model immunization. Surprisingly, treatment with SU5416, an inhibitor of VEGF and other receptor tyrosine kinases, did not have sustained effects in inhibiting vascular growth, but attenuated the anti-dsDNA response and altered the phenotype of the double negative T cells that are expanded in these mice. In examining for anatomic correlates of these immunologic changes, we found that the double negative T cells are localized within ectopic follicles around a central B cell patch and that these T cell-rich areas lack the T zone stromal protein ER-TR7 as well as other elements of a normal T zone microenvironment. SU5416 treatment disrupted these follicles and normalized the association between T zone microenvironmental elements and T cell-rich areas. Recent studies have shown a regulatory role for T zone stromal elements. Thus, our findings of the association of anti-dsDNA responses, double negative T cell phenotype, and altered lymphocyte microenvironment suggest the possibility that lymphocyte localization in ectopic follicles protects them from regulation by T zone stromal elements and functions to maintain autoimmune responses. Potentially, altering the lymphocyte microenvironment that is set up by the vascular-stromal compartment can be a means by which to control undesired autoimmune responses

Vampires in the village Žrnovo on the island of Korčula: following an archival document from the 18th century

Središnja tema rada usmjerena je na raščlambu spisa pohranjenog u Državnom arhivu u Mlecima (fond: Capi del Consiglio de’ Dieci: Lettere di Rettori e di altre cariche) koji se odnosi na događaj iz 1748. godine u korčulanskom selu Žrnovo, kada su mještani – vjerujući da su se pojavili vampiri – oskvrnuli nekoliko mjesnih grobova. U radu se podrobno iznose osnovni podaci iz spisa te rečeni događaj analizira u širem društvenom kontekstu i prate se lokalna vjerovanja.The main interest of this essay is the analysis of the document from the State Archive in Venice (file: Capi del Consiglio de’ Dieci: Lettere di Rettori e di altre cariche) which is connected with the episode from 1748 when the inhabitants of the village Žrnove on the island of Korčula in Croatia opened tombs on the local cemetery in the fear of the vampires treating. This essay try to show some social circumstances connected with this event as well as a local vernacular tradition concerning superstitions

Contribution of B cell subsets to delayed development of MAIDS in xid mice.

C57BL/6 (B6) mice develop a syndrome of progressive lymphoproliferation and immunodeficiency, murine AIDS (MAIDS), when infected with an etiologic replication-defective virus termed BM5def. Induction of MAIDS requires the presence of CD4+ T cells and B cells. B6 mice with altered conventional B cell function and a deficit in CD5+ B cells due to the xid mutation develop disease with a greatly prolonged latency. The association of this mutation with resistance to MAIDS was confirmed in studies of P.xid mice. To test the hypothesis that conventional B cells are required for rapid induction of disease, B6.xid mice were injected with spleen cells from nude mice or were given bone marrow from aged donors. Both sets of recipients developed advanced disease by 10 weeks post infection, suggesting that resistance to MAIDS in xid mutants may be due to effects of B cells other than the CD5+ subset