PMID- 2168113
OWN - NLM
STAT- MEDLINE
DCOM- 19901002
LR  - 20190907
IS  - 0168-1702 (Print)
IS  - 0168-1702 (Linking)
VI  - 16
IP  - 3
DP  - 1990 Jul
TI  - Influence of mammary cell differentiation on the expression of proteins encoded 
      by endogenous BALB/c mouse mammary tumor virus genes.
PG  - 307-23
AB  - The interactions between differentiation-associated cellular events in the intact 
      mammary gland or in cultured mammary cells and the post-transcriptional activity 
      of the endogenous mouse mammary tumor virus (MMTV) loci were investigated. The 
      transcriptional activities of the endogenous MMTV proviruses of the BALB/c mouse 
      strain (Mtv-6, Mtv-8 and Mtv-9) appear to be regulated differentially during 
      pregnancy-induced mammary gland development (J.E. Knepper, D. Medina and J.S. 
      Butel, J. Virol. 59, 518-521, 1986). Analysis of MMTV-specific proteins at 
      various stages of mammary gland development (virgin, midpregnant, lactating, 
      regressing) established the presence of steady-state levels of a 67,000-Mr env 
      precursor-type polypeptide at all physiological stages. However, processing to 
      lower-molecular-weight env-specific proteins, including a predominant 50,000-Mr 
      species, was detected only with the transition to the functional mammary gland 
      phenotype. The contributions of cell proliferation, cell-matrix interactions, and 
      modulation of functional activity to the pattern of endogenous MMTV protein 
      expression were investigated using a 3-dimensional collagen type I culture 
      system. Growth and cell-matrix interactions (cell polarization, lumen formation) 
      leading to formation of 3-dimensional duct-like structures were permissive for 
      the synthesis and processing of MMTV-specific proteins; accumulation of high 
      levels of the 50,000-Mr env-specific polypeptide was associated with the onset of 
      the fully functional mammary cell phenotype. Expression of MMTV-specific proteins 
      was not due to amplification of a specific cell subpopulation. The potential of 
      the full-length Mtv-8 and Mtv-9 proviruses to be transcribed, as indicated by 
      their methylation status, was not dramatically different between differentiated 
      and undifferentiated mammary cells in culture. This study indicates that MMTV 
      transcriptional activity is reflected at the protein level in mammary tissue of 
      BALB/c mice and that viral protein synthesis and processing may serve as 
      important markers of different physiological stages of mammary epithelial cells. 
      These observations also suggest a general approach to the examination of 
      potential modulatory effects of cellular interactions (cell-cell, cell-matrix or 
      both) known to be important in various differentiated epithelial cell systems for 
      the expression of viral genes.
FAU - Durban, E M
AU  - Durban EM
AD  - Oral Diagnostic Sciences Department, University of Texas Dental Branch, Houston.
FAU - Knepper, J E
AU  - Knepper JE
FAU - Medina, D
AU  - Medina D
FAU - Butel, J S
AU  - Butel JS
LA  - eng
GR  - CA25215/CA/NCI NIH HHS/United States
GR  - CA33369/CA/NCI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - Netherlands
TA  - Virus Res
JT  - Virus research
JID - 8410979
RN  - 0 (Caseins)
RN  - 0 (Viral Envelope Proteins)
RN  - 4964P6T9RB (Aldosterone)
RN  - 9002-62-4 (Prolactin)
RN  - WI4X0X7BPJ (Hydrocortisone)
SB  - IM
MH  - Aldosterone/pharmacology
MH  - Animals
MH  - Caseins/biosynthesis
MH  - Cell Differentiation
MH  - Cells, Cultured
MH  - Electrophoresis, Polyacrylamide Gel
MH  - Epithelium/drug effects
MH  - Female
MH  - *Gene Expression Regulation, Viral
MH  - Hydrocortisone/pharmacology
MH  - Immunoblotting
MH  - Mammary Glands, Animal/*cytology/drug effects/microbiology
MH  - Mammary Tumor Virus, Mouse/drug effects/*genetics
MH  - Methylation
MH  - Mice
MH  - Mice, Inbred BALB C
MH  - Pregnancy
MH  - Prolactin/pharmacology
MH  - Proviruses/genetics/metabolism
MH  - Transcription, Genetic/genetics
MH  - Viral Envelope Proteins/*biosynthesis/genetics
MH  - Virus Activation/genetics
EDAT- 1990/07/01 00:00
MHDA- 1990/07/01 00:01
CRDT- 1990/07/01 00:00
PHST- 1990/07/01 00:00 [pubmed]
PHST- 1990/07/01 00:01 [medline]
PHST- 1990/07/01 00:00 [entrez]
AID - 0168-1702(90)90055-G [pii]
AID - 10.1016/0168-1702(90)90055-g [doi]
PST - ppublish
SO  - Virus Res. 1990 Jul;16(3):307-23. doi: 10.1016/0168-1702(90)90055-g.