PMID- 2157765
OWN - NLM
STAT- MEDLINE
DCOM- 19900517
LR  - 20141120
IS  - 0022-1767 (Print)
IS  - 0022-1767 (Linking)
VI  - 144
IP  - 8
DP  - 1990 Apr 15
TI  - Molecular events in B lymphocyte differentiation. Inducible expression of the 
      endogenous mouse mammary tumor proviral gene, Mtv-9.
PG  - 3218-27
AB  - We have previously shown that the steady state levels of transcripts encoded by 
      an endogenous mouse mammary tumor virus (MMTV) increase during LPS-induced 
      differentiation of both normal B lymphocytes and an inducible B cell lymphoma, 
      CH12. A large body of evidence suggests that MMTV expression is primarily limited 
      to mammary tissues and that expression in cell lines from nonmammary tissues is 
      accompanied by viral amplification and alterations in the transcriptional control 
      regions of the viral long terminal repeat. We have, therefore, carefully 
      characterized MMTV expression in CH12 cells and in other cells of the B lineage 
      in order to determine if the expression of MMTV transcripts in differentiating B 
      cells results from the "abnormal" transcriptional regulation seen in other 
      nonmammary tissue. In this manuscript, we present evidence that MMTV transcripts 
      are expressed in a variety of cells of the B lineage and that the levels of 
      constitutive expression vary among the different cells. On the other hand, T cell 
      lymphomas lacking amplified MMTV do not contain proviral transcripts, suggesting 
      that MMTV transcription may be preferentially expressed in B lymphocytes. We 
      demonstrate that MMTV transcripts are up-regulated during cytokine-mediated as 
      well as LPS-mediated differentiation, and that most, if not all, expression is 
      due to the activity of a single proviral gene, Mtv-9, in CH12 cells. Furthermore, 
      the expression of MMTV transcripts in CH12 cells neither requires nor is 
      accompanied by amplification of the provirus. Sequence analysis demonstrates that 
      the U3 region of the expressed Mtv-9 long terminal repeat contains neither 
      deletions nor insertions, and the well-characterized enhancer and promoter sites 
      in the glucocorticoid response element which are known to be involved in 
      transcriptional regulation of MMTV in mammary tissues have not been disrupted. 
      These data suggest that the Mtv-9 locus behaves as a normal somatic gene which is 
      differentially regulated during B cell development and differentiation. Unlike 
      the events which lead to MMTV expression in other nonmammary tissues, B cells may 
      express transcription factor(s) which are capable of inducing expression of 
      endogenous MMTV proviral genes during the natural course of differentiation. 
      Analysis of the mechanisms which control the expression of this gene should be 
      useful in characterizing the molecular events which govern B cell 
      differentiation.
FAU - King, L B
AU  - King LB
AD  - Department of Microbiology and Immunology, Duke University Medical Center, 
      Durham, NC 27710.
FAU - Lund, F E
AU  - Lund FE
FAU - White, D A
AU  - White DA
FAU - Sharma, S
AU  - Sharma S
FAU - Corley, R B
AU  - Corley RB
LA  - eng
SI  - GENBANK/M29600
GR  - 5 T32 CA09058/CA/NCI NIH HHS/United States
GR  - 5 T32 GM07184/GM/NIGMS NIH HHS/United States
GR  - CA36642/CA/NCI NIH HHS/United States
GR  - etc.
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Immunol
JT  - Journal of immunology (Baltimore, Md. : 1950)
JID - 2985117R
RN  - 0 (Gene Products, env)
RN  - 0 (Lipopolysaccharides)
RN  - 0 (RNA, Viral)
SB  - IM
MH  - Animals
MH  - B-Lymphocytes/*cytology/microbiology/physiology
MH  - Base Sequence
MH  - Blotting, Southern
MH  - Cell Differentiation/drug effects
MH  - Cloning, Molecular
MH  - Gene Amplification
MH  - Gene Expression Regulation/drug effects
MH  - Gene Products, env/genetics
MH  - Genes, Viral
MH  - In Vitro Techniques
MH  - Lipopolysaccharides/pharmacology
MH  - Mammary Tumor Virus, Mouse/*genetics
MH  - Mice
MH  - Molecular Sequence Data
MH  - RNA, Viral/biosynthesis
MH  - Restriction Mapping
MH  - T-Lymphocytes/microbiology/physiology
MH  - Transcription, Genetic
MH  - Tumor Cells, Cultured
EDAT- 1990/04/15 00:00
MHDA- 1990/04/15 00:01
CRDT- 1990/04/15 00:00
PHST- 1990/04/15 00:00 [pubmed]
PHST- 1990/04/15 00:01 [medline]
PHST- 1990/04/15 00:00 [entrez]
PST - ppublish
SO  - J Immunol. 1990 Apr 15;144(8):3218-27.