scholarly journals Secretory proteins compete for production in the mammary gland of transgenic mice

1995 ◽  
Vol 310 (2) ◽  
pp. 637-641 ◽  
Author(s):  
M McClenaghan ◽  
A Springbett ◽  
R M Wallace ◽  
C J Wilde ◽  
A J Clark
Keyword(s):  
Mammary Gland ◽  
Transgenic Mice ◽  
Milk Protein ◽  
Milk Proteins ◽  
Whey Acidic Protein ◽  
Acidic Protein ◽  
Host Protein ◽  
Secretory Proteins ◽  
Mrna Levels ◽  
Endogenous Proteins

To explore the possibility that genes might compete for expression, we have studied transgenic mice producing high levels of the sheep milk protein, beta-lactoglobulin (BLG), in the mammary gland. Mice carrying one or more transgene loci expressed BLG in milk at levels ranging from 7 to 33 mg/ml. The effects of BLG synthesis on the levels of endogenous milk gene expression were examined. No significant increase in total milk protein concentration was recorded even in mice expressing the largest amounts of BLG. Measurement of individual milk proteins showed that transgene protein was manufactured at the expense of host protein synthesized in the gland. Whey acidic protein production was more suppressed than casein production. Suppression of endogenous proteins was matched by a reduction in the corresponding steady-state mRNA levels; in double-transgenic mice, which expressed the largest amounts of BLG, beta-casein and whey acidic protein mRNA populations were reduced to 75 and 56% of control levels respectively. We demonstrate that an exogenous gene competes effectively for expression with endogenous genes. Possible mechanisms of competition are discussed.

The effect of low-to-moderate-dose ethanol consumption on rat mammary gland structure and function and early postnatal growth of offspring

2013 ◽  
Vol 304 (10) ◽  
pp. R791-R798 ◽  
Author(s):  
Megan E. Probyn ◽  
Emma-Kate Lock ◽  
Stephen T. Anderson ◽  
Sarah Walton ◽  
John F. Bertram ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Alcohol Consumption ◽  
Milk Proteins ◽  
Postnatal Growth ◽  
Whey Acidic Protein ◽  
Acidic Protein ◽  
Postnatal Life ◽  
Sprague Dawley ◽  
Moderate Dose ◽  
Protein Levels

High levels of alcohol consumption during pregnancy can lead to growth deficits in early postnatal life. However, the effects of low-to-moderate alcohol consumption during pregnancy are less clearly defined. The aim of this study was to determine whether low-to-moderate ethanol (EtOH) consumption throughout pregnancy in the rat alters maternal mammary gland morphology and milk protein levels, thereby affecting lactation and the growth of pups after birth. Sprague-Dawley rats were fed an ad libitum liquid diet ± 6% vol/vol EtOH throughout pregnancy. Mammary glands from dams were collected at embryonic day (E) 20 or postnatal day (PN) 1, and expression of milk proteins (α-lactalbumin, β-casein, and whey acidic protein) was examined. In addition, relative amounts of alveoli, lactiferous ducts, adipose tissue, and blood vessels were determined at PN1. A subset of rats gave birth, and offspring growth and milk intake were recorded. Mammary gland weight was unaltered by EtOH, and stereological analysis showed no differences in gland structure compared with control. Although there were no significant changes in mammary gland gene expression at the RNA level, protein levels of α-lactalbumin were increased and whey acidic protein were decreased by EtOH. Offspring of EtOH-fed dams consumed less milk than controls in the lactational period; however, this did not alter their early postnatal growth. Overall, it appears that low-to-moderate-dose prenatal EtOH exposure does not significantly alter mammary gland development but may alter the composition of the various proteins found within the milk in a manner that maintains overall pup growth.

Rabbit whey acidic protein gene upstream region controls high-level expression of bovine growth hormone in the mammary gland of transgenic mice

1995 ◽  
Vol 42 (3) ◽  
pp. 261-267 ◽  
Author(s):  
Dominique Thépot ◽  
Eve Devinoy ◽  
Marie-Louise Fontaine ◽  
Marie-Georges Stinnakre ◽  
Micheline Massoud ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Mammary Gland ◽  
Transgenic Mice ◽  
Protein Gene ◽  
Whey Acidic Protein ◽  
Acidic Protein ◽  
Upstream Region ◽  
Bovine Growth Hormone ◽  
High Level Expression ◽  
High Level

Gene expression of leptin, leptin receptor, prolactin receptor and whey acidic protein in mammary glands of late-pregnant gilts from two breeds

2004 ◽  
Vol 84 (4) ◽  
pp. 621-629 ◽  
Author(s):  
M. F. Palin ◽  
D. Beaudry ◽  
C. Farmer
Keyword(s):  
Gene Expression ◽  
Mammary Gland ◽  
Leptin Receptor ◽  
Prolactin Receptor ◽  
Mammary Glands ◽  
Whey Acidic Protein ◽  
Acidic Protein ◽  
Mrna Levels ◽  
Parenchymal Tissue ◽  
Receptor Mrna

In order to identify genes which are essential for pig mammary gland development, mRNA levels of prolactin receptor (PRL-R), leptin, leptin receptor and whey acidic protein (WAP) were measured in parenchymal tissue of 110-d-pregnant gilts. Thirteen Upton-Meishan (UM) and 14 Large White (LW) pregnant gilts and 5 non-pregnant control gilts (2 LW and 3UM) were used. PRL-R and WAP mRNA levels were higher in pregnant than in non-pregnant gilts (P < 0.05). Leptin mRNA levels were higher in UM than in LW gilts (P < 0.05), but this breed effect was not seen when leptin mRNA levels were corrected for percent fat in parenchyma. Correlations were found between concentrations of IGF-I in plasma and PRL-R (P < 0.01) and WAP (P < 0.05) mRNA levels in UM gilts. Serum prolactin (PRL) was correlated with leptin mRNA levels in the overall (P < 0.05) and LW (P < 0.05) populations of gilts, while estradiol was associated with leptin receptor mRNA in UM gilts (P < 0.05). The mRNA levels of all studied genes were positively correlated with mammary parenchymal and extra parenchymal weights in UM gilts, whereas these variables were only correlated with PRL-R and WAP gene expression in LW gilts. The presence of leptin and leptin receptor mRNA in parenchymal tissue suggests a paracrine role for leptin in mammary tissue of late-pregnant gilts. These results also suggest that the PRL signalling pathway is fully active at the transcriptional level in the mammary gland of gilts at 110 d of pregnancy. Key words: Genetics, pig, mammary glands, Meishan, mRNA

scholarly journals Relative distribution of post-nuclear poly(A)-containing RNA abundance groups within the nuclear and post-nuclear polyadenylated and non-polyadenylated RNA populations of the lactating guinea-pig mammary gland

1980 ◽  
Vol 192 (2) ◽  
pp. 489-498 ◽  
Author(s):  
Ian C. Bathurst ◽  
Roger K. Craig ◽  
David G. Herries ◽  
Peter N. Campbell
Keyword(s):  
Mammary Gland ◽  
Guinea Pig ◽  
Milk Protein ◽  
Regulation Of Gene Expression ◽  
Milk Proteins ◽  
Relative Distribution ◽  
Free System ◽  
Low Salt ◽  
Nuclear Rna ◽  
System 2

1. RNA isolated from the post-nuclear supernatant of the lactating guinea-pig mammary gland was fractionated with oligo(dT)–cellulose into three populations; those that bound at ‘low salt’ [long poly(A) tracts, 78–32 nucleotides]; those that bound at ‘high salt’ [shorter poly(A) tracts, 48–21 nucleotides]; and those that did not bind [no poly(A) or short poly(A) tracts, <20 nucleotides]. Nuclear RNA was fractionated into two populations, those that bound in ‘low salt’ and those that did not bind. All the post-nuclear RNA fractions directed the synthesis of milk proteins in a Krebs II ascites cell-free system. 2. 3H-labelled DNA complementary to the post-nuclear poly-(A)-containing RNA population (low-salt fraction) was fractionated into abundant (milk-protein mRNA), moderately abundant and scarce sequences. This complementary DNA was then used to investigate the distribution of the mRNA sequences in the different RNA populations. This showed that all sequences were present in polyadenylated and non-polyadenylated fractions, but that major quantitative differences were apparent. The abundant milk-protein mRNA sequences predominated in the ‘low-salt’ post-nuclear poly(A)-containing RNA fraction, whereas the moderately abundant sequences predominated in the non-polyadenylated post-nuclear RNA fraction. In total cellular RNA, those sequences deemed initially to be moderately abundant within the ‘low-salt’ poly(A)-containing RNA population were present at a concentration very similar to those of the abundant milk-protein mRNA (approx. 6×105 copies of each sequence/cell). Similarly, analysis of the nuclear RNA populations showed that the ‘abundant’ and so-called ‘moderately abundant’ sequences were present in essentially identical concentrations (2×103 copies of each sequence/cell). The majority of these (90–95%) were non-polyadenylated. 3. The results are discussed in terms of the post-transcriptional mechanisms involved in the regulation of gene expression in the lactating guinea-pig mammary gland.

A distal region, hypersensitive to DNase I, plays a key role in regulating rabbit whey acidic protein gene expression

2001 ◽  
Vol 359 (3) ◽  
pp. 557-565 ◽  
Author(s):  
Benjamin MILLOT ◽  
Marie-Louise FONTAINE ◽  
Dominique THEPOT ◽  
Eve DEVINOY
Keyword(s):  
Mammary Gland ◽  
Sequence Similarity ◽  
Distal Region ◽  
Dnase I ◽  
Whey Acidic Protein ◽  
Acidic Protein ◽  
Upstream Region ◽  
Lactating Mammary Gland

The aim of the present study was to identify the functional domains of the upstream region of the rabbit whey acidic protein (WAP) gene, which has been used with considerable efficacy to target the expression of several foreign genes to the mammary gland. We have shown that this region exhibits three sites hypersensitive to DNase I digestion in the lactating mammary gland, and that all three sites harbour elements which can bind to Stat5 in vitro in bandshift assays. However, not all hypersensitive regions are detected at all stages from pregnancy to weaning, and the level of activated Stat5 detected in the rabbit mammary gland is low except during lactation. We have studied the role of the distal site, which is only detected during lactation, in further detail. It is located within a 849bp region that is required to induce a strong expression of the chloramphenicol acetyltransferase reporter gene in transfected mammary cells. Taken together, these results suggest that this region, centred around a Stat5-binding site and surrounded by a variable chromatin structure during the pregnancy–lactation cycle, may play a key role in regulating the expression of this gene in vivo. Furthermore, this distal region exhibits sequence similarity with a region located around 3kb upstream of the mouse WAP gene. The existence of such a distal region in the mouse WAP gene may explain the differences in expression between 4.1 and 2.1kb mouse WAP constructs.

scholarly journals Nuclear factor I and mammary gland factor (STAT5) play a critical role in regulating rat whey acidic protein gene expression in transgenic mice.

1995 ◽  
Vol 15 (4) ◽  
pp. 2063-2070 ◽  
Author(s):  
S Li ◽  
J M Rosen
Keyword(s):  
Gene Expression ◽  
Mammary Gland ◽  
Transgenic Mice ◽  
Binding Sites ◽  
Transgene Expression ◽  
Protein Gene ◽  
Whey Acidic Protein ◽  
Nuclear Factor ◽  
Factor I ◽  
Nuclear Factor I

The rat whey acidic protein (WAP) gene contains a mammary gland-specific and hormonally regulated DNase I-hypersensitive site 830 to 720 bp 5' to the site of transcription initiation. We have reported previously that nuclear factor I (NFI) binding at a palindromic site and binding at a half-site are the major DNA-protein interactions detected within this tissue-specific nuclease-hypersensitive region. We now show that point mutations introduced into these NFI-binding sites dramatically affect WAP gene expression in transgenic mice. Transgene expression was totally abrogated when the palindromic NFI site or both binding sites were mutated, suggesting that NFI is a key regulator of WAP gene expression. In addition, a recognition site for mammary gland factor (STAT5), which mediates prolactin induction of milk protein gene expression, was also identified immediately proximal to the NFI-binding sites. Mutation of this site reduced transgene expression by approximately 90% per gene copy, but did not alter tissue specificity. These results suggest that regulation of WAP gene expression is determined by the cooperative interactions among several enhancers that constitute a composite response element.

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