Cloning of an Infectious Milk-Borne Mouse Mammary Tumor Virus (MMTV) DNA from a Mammary Tumor That Developed in an Endogenous MMTV-Free Wild Mouse

Abstract

Molecular characterization of infectious mouse mammary tumor viruses (MMTVs) has been hampered due to the problem of cloning a full-length exogenous virus into a plasmid. The present report describes our strategy for obtaining a full-length clone of an exogenous MMTV from a mouse mammary tumor that arose spontaneously in a wild Chinese mouse free of endogenous MMTV and shows that the cloned virus (JYG-MMTV) is expressed in rat RBA cells. Four-week-old C58/J x CBA/CaJ female mice, free of both endogenous and exogenous MMTVs, were injected with virus-secreting RBA cells. The progeny of these mice were bred, and their offspring were tested for the presence of MMTV. These third-generation mice were found to actively produce MMTV that was shed in their milk and transmitted to their offspring. The virus was detected not only in the mammary glands of these young mice, but also in their spleens and bone marrow. These results suggest that our plasmid-cloned exogenous JYG-MMTV is infectious. This virus can now be used effectively in manipulating the various genes of JYG-MMTV and other MMTV strains to understand their structure/function relationships.

Séquences provenant d’éléments génétiques mobiles, face cachée du génome humain

“…On parle alors de génome proviral ou de provirus. Les rétrovirus endogènes sont rarement infectieux, mais certains ERV infectieux ont été identifiés chez des mammifères [6,7]. Comme illustré dans la Figure 1, ils correspondent pour la plupart à des « vestiges génétiques » d'anciens virus exogènes dont des séquences ont colonisé notre génome et ont été transmises verticalement, parfois avec de nouvelles rétrotranspositions ou des réarrangements somatiques, voire des réinfections fréquentes de la lignée germinale, par un virus exogène de l'environnement au cours de certaines périodes de l'évolution [8,9].…”

The Noncanonical Gag Domains p8 and n Are Critical for Assembly and Release of Mouse Mammary Tumor Virus

“…It has been reported elsewhere that rat cells are susceptible to MMTV infection (5,15) and transfection by some MMTV hybrid constructs (19). Unfortunately, in contrast to 293T cells, the mammary gland cells do not support episomal replication of simian virus 40 (SV40) origin-containing plasmids like the pSMt-HYB-derived constructs.…”

Endogenous retroviral genes, Herpesviruses and gender in Multiple Sclerosis

“…Members of Endogenous Retrovirus families (ERVs) have been mostly studied in animals; for example mouse leukaemia viruses, mouse mammary tumour viruses and ovine pulmonary carcinoma viruses [5,6,10,19,89]. They are known to include few exogenous and/ or horizontally transmissible strains.…”