scholarly journals Regulation of mouse mammary-gland γ-glutamyltranspeptidase mRNA during pregnancy, lactation and weaning

1990 ◽  
Vol 267 (3) ◽  
pp. 621-624 ◽  
Author(s):  
S Siegrist ◽  
Y Laperche ◽  
M N Chobert ◽  
F Bulle ◽  
H L Nakhasi ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Blot Analysis ◽  
Southern Blot Analysis ◽  
Mouse Mammary Gland ◽  
Convincing Evidence ◽  
Physiological Regulation ◽  
Faint Band ◽  
High Level ◽  
Specific Mrna ◽  
Virgin Mouse

The level of gamma-glutamyltranspeptidase (GGT) activity and of its mRNA were determined in the mouse mammary gland during pregnancy, lactation and weaning. The GGT activity, which is very low in the virgin-mouse mammary gland (5 munits/mg of protein), increases progressively during pregnancy (3-fold), reaches its maximum at the onset of lactation (8-fold) and returns rapidly to basal level at weaning. Although no GGT-specific mRNA is detected in the virgin-mouse mammary gland, a single faint band of 2.2 kb in size is found during pregnancy. During lactation, an additional mRNA of 2.4 kb in size appears, and the level of both mRNAs is higher. This high level of mRNA persists during weaning as well. Southern-blot analysis of mouse mammary-gland DNA provides convincing evidence that there is only one gene which codes for the two mRNAs. The present study provides the first evidence for a physiological regulation of the two GGT mRNAs in the same tissue.

scholarly journals Dissociation of cytological and functional differential in virgin mouse mammary gland during inhibition of DNA synthesis

1982 ◽  
Vol 53 (1) ◽  
pp. 97-114 ◽  
Author(s):  
B.K. Vonderhaar ◽  
G.H. Smith
Keyword(s):  
Mammary Gland ◽  
Epithelial Cells ◽  
Dna Synthesis ◽  
Milk Protein ◽  
Light And Electron Microscopy ◽  
Mouse Mammary Gland ◽  
Enhanced Production ◽  
Virgin Mouse ◽  
In Cells

Epithelial cells in mammary gland explants from mice assume a secretory appearance and synthesize the milk proteins, casein and alpha-lactalbumin, when cultured in the presence of insulin, hydrocortisone and prolactin. In cells from the glands of mature virgin animals such syntheses are known to require DNA synthesis. Addition of cytosine-beta-D-arabinofuranoside to the explant cultures suppresses both hormonally induced DNA synthesis and enhanced production of milk protein. To determine the level at which this block in terminal differentiation occurs, epithelial cell pellets were prepared from virgin mouse mammary gland explants cultured with various combination of insulin, hydrocortisone and prolactin, and subsequently examined by light and electron microscopy. We observed that the epithelial cells cultured in the presence of all three hormones developed fully, cytologically and ultrastructurally, even in the absence of DNA synthesis in vitro. Likewise, these cells were able to incorporate [3H]uridine into RNA efficiently and to incorporate amino acids into acid-precipitable polypeptides at levels equivalent to the untreated controls. However, immunoprecipitation of newly synthesized casein peptides showed that no new synthesis of casein occurred in cells prevented from synthesizing DNA. These data show uncoupling of cytological development and synthesis of milk protein in mammary explants from mature virgin mice inhibited from synthesizing DNA.

scholarly journals The interdependence of mammary-specific super-enhancers and their native promoters facilitates gene activation during pregnancy

2020 ◽  
Vol 52 (4) ◽  
pp. 682-690
Author(s):  
Xianke Zeng ◽  
Hye Kyung Lee ◽  
Chaochen Wang ◽  
Precious Achikeh ◽  
Chengyu Liu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Mammary Gland ◽  
Gene Activation ◽  
Mouse Mammary Gland ◽  
High Level Expression ◽  
Heterologous Promoter ◽  
Native Promoter ◽  
Super Enhancer ◽  
Pregnancy And Lactation ◽  
High Level

Abstract Lineage-specific genetic programs rely on cell-restricted super-enhancers, which are platforms for high-density transcription factor occupation. It is not known whether super-enhancers synergize specifically with their native promoters or provide autonomous and independent regulatory platforms. Here, we investigated the ability of the mammary Wap super-enhancer to activate the promoter of the juxtaposed and ubiquitously expressed Tbrg4 gene in the mouse mammary gland. The Wap super-enhancer was fused, alone or in combination with the Wap promoter, to the Tbrg4 gene. While the super-enhancer increased the expression of the Tbrg4 promoter five-fold, the combination of the super-enhancer and promoter resulted in 80-fold gene upregulation, demonstrating lineage-specific promoter–enhancer synergy. Employing ChIP-seq profiling to determine transcription factor binding and identify activating histone marks, we uncovered a chromatin platform that enables the high-level expression of the native promoter–enhancer but not the heterologous promoter. Taken together, our data reveal that lineage-specific enhancer–promoter synergy is critical for mammary gene regulation during pregnancy and lactation.

Electron microscopic studies on ultrathin frozen sections of lactating mouse mammary gland

1978 ◽  
Vol 36 (2) ◽  
pp. 46-47
Author(s):  
Jan Zarzycki ◽  
Joseph Szroeder
Keyword(s):  
Mammary Gland ◽  
Protein Denaturation ◽  
Chemical Constituents ◽  
Freeze Substitution ◽  
Electron Microscopic Examination ◽  
Mouse Mammary Gland ◽  
Electron Microscopic ◽  
Preparation Methods ◽  
Microscopic Studies ◽  
Ultrathin Frozen Sections

The mammary gland ultrastructure in various functional states is the object of our investigations. The material prepared for electron microscopic examination by the conventional chemical methods has several limitations, the most important are the protein denaturation processes and the loss of large amounts of chemical constituents from the cells. In relevance to this,one can't be sure about a degree the observed images are adequate to the realy ultrastructure of a living cell. To avoid the disadvantages of the chemical preparation methods,some autors worked out alternative physical methods based on tissue freezing / freeze-drying, freeze-substitution, freeze-eatching techniqs/; actually the technique of cryoultraraicrotomy,i,e.cutting ultrathin sections from deep frozen specimens is assented as a complete alternative method. According to the limitations of the routine plastic embbeding methods we were interested to analize the mammary gland ultrastructure during lactation by the cryoultramicrotomy method.

mRNA expression of lipogenic genes in mouse mammary gland in different lactation stages

2012 ◽  
Vol 34 (3) ◽  
pp. 335-341
Author(s):  
Li-Qiang HAN ◽  
Hong-Ji LI ◽  
Yue-Ying WANG ◽  
Lin-Feng WANG ◽  
Guo-Qing YANG ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Mrna Expression ◽  
Mouse Mammary Gland ◽  
Lipogenic Genes
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