Potential progenitor sequences of mink cell focus-forming (MCF) murine leukemia viruses: ecotropic, xenotropic, and MCF-related viral RNAs are detected concurrently in thymus tissues of AKR mice.
Leukemogenic mink cell focus-forming (MCF) viruses of AKR mice are believed to originate in thymic tissue via recombination between ecotropic, xenotropiclike, and endogenous MCF-related murine leukemia virus (MuLV) sequences. We have previously used a synthetic 16-base-pair MCF env-specific oligomer probe to identify subgenomic MCF-related mRNAs present in the thymus tissues of AKR mice prior to the appearance of full-length (8.4-kilobase [kb]) recombinant MCF viral RNAs (A. S. Khan, F. Laigret, and C. P. Rodi, J. Virol. 61:876-882, 1987). These potential MCF env precursors consisted of 7.2-, 3.0-, and 1.8-kb RNA species. In this study, we have determined the structure of the MCF-related mRNAs on the basis of Northern (RNA) blot hybridization analyses by using 10 different MuLV subgenomic DNA probes, determined the nucleotide sequence of a cloned cDNA segment representing the 3' portion of the 7.2-kb mRNA, and studied the expression of ecotropic and xenotropic MuLV sequences by using env-specific DNA probes. The results indicated that ecotropic, xenotropic, and MCF-related transcripts were constitutively and concurrently expressed exclusively in thymus tissue of 2-month-old AKR mice prior to detection of MCF viral RNAs. We have molecularly characterized these thymic MuLV RNAs, which may participate in formation of recombinant MCF viruses; a novel recombinant ecotropic viral RNA was identified as a putative intermediate in the stepwise generation of leukemogenic MCF MuLVs. We have also described the unique structure of the 6.0-kb MCF-related RNAs which were expressed specifically in liver and kidney tissues of AKR mice; these RNAs contained an upstream non-MuLV transcriptional regulatory element.
Laigret
F
F
Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892.
Repaske
R
R
Boulukos
K
K
Rabson
A B
AB
Khan
A S
AS
D000595:Amino Acid Sequence; D000818:Animals; D001345:Autoradiography; D001483:Base Sequence; D003001:Cloning, Molecular; D004279:DNA, Viral / Q000235:genetics; D005814:Genes, Viral; D007700:Kinetics; D009052:Leukemia Virus, Murine / Q000235:genetics*; D051379:Mice; D008806:Mice, Inbred AKR; D008908:Mink Cell Focus-Inducing Viruses / Q000235:genetics*; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D012322:RNA Precursors / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D012367:RNA, Viral / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid; D013950:Thymus Gland / Q000382:microbiology*; D014158:Transcription, Genetic
D004279:DNA, Viral; D012322:RNA Precursors; D012333:RNA, Messenger; D012367:RNA, Viral