Differential regulation of rat beta-casein-chloramphenicol acetyltransferase fusion gene expression in transgenic mice

1989 ◽  
Vol 9 (2) ◽  
pp. 560-565
Author(s):  
K F Lee ◽  
S H Atiee ◽  
J M Rosen
Keyword(s):  
Gene Expression ◽  
Mammary Gland ◽  
Transgenic Mice ◽  
Fusion Gene ◽  
Chloramphenicol Acetyltransferase ◽  
Fusion Genes ◽  
Specific Expression ◽  
Casein Gene ◽  
Noncoding Exon ◽  
Beta Casein

Previous studies in our laboratory have demonstrated the mammary-specific expression of the entire rat beta-casein gene with 3.5 kilobases (kb) of 5' and 3.0 kb of 3' DNA in transgenic mice (Lee et al., Nucleic Acids Res. 16:1027-1041, 1988). In an attempt to localize sequences that dictate this specificity, lines of transgenic mice carrying two different rat beta-casein promoter-bacterial chloramphenicol acetyltransferase (cat) fusion genes have been established. Twenty and eight lines of transgenic mice carrying two fusion genes containing either 2.3 or 0.5 kb, respectively, of 5'-flanking DNA of the rat beta-casein gene along with noncoding exon I and 0.5 kb of intron A were identified, most of which transmitted the transgenes to their offspring in a Mendelian pattern. CAT activity was detected predominantly in the lactating mammary gland of female transgenic mice but not in the male mammary fat pad. A several-hundred-fold variation in the level of cat expression was observed in the mammary gland of different lines of mice, presumably due to the site of integration of the transgenes. CAT activity was increased in the mammary gland during development from virgin to midpregnancy and lactation. Unexpectedly, the casein-cat transgenes were also expressed in the thymus of different lines of both male and female mice, in some cases at levels equivalent to those observed in the mammary gland, and in contrast to the mammary gland, CAT activity was decreased during pregnancy and lactation in the thymus. Thus, 0.5 kb of 5'-flanking DNA of the rat beta-casein gene along with noncoding exon I and 0.5 kb of intron A are sufficient to target bacterial cat gene expression to the mammary gland of lactating mice.

scholarly journals Differential regulation of rat beta-casein-chloramphenicol acetyltransferase fusion gene expression in transgenic mice.

1989 ◽  
Vol 9 (2) ◽  
pp. 560-565 ◽  
Author(s):  
K F Lee ◽  
S H Atiee ◽  
J M Rosen
Keyword(s):  
Gene Expression ◽  
Mammary Gland ◽  
Transgenic Mice ◽  
Fusion Gene ◽  
Chloramphenicol Acetyltransferase ◽  
Fusion Genes ◽  
Specific Expression ◽  
Casein Gene ◽  
Noncoding Exon ◽  
Beta Casein

Previous studies in our laboratory have demonstrated the mammary-specific expression of the entire rat beta-casein gene with 3.5 kilobases (kb) of 5' and 3.0 kb of 3' DNA in transgenic mice (Lee et al., Nucleic Acids Res. 16:1027-1041, 1988). In an attempt to localize sequences that dictate this specificity, lines of transgenic mice carrying two different rat beta-casein promoter-bacterial chloramphenicol acetyltransferase (cat) fusion genes have been established. Twenty and eight lines of transgenic mice carrying two fusion genes containing either 2.3 or 0.5 kb, respectively, of 5'-flanking DNA of the rat beta-casein gene along with noncoding exon I and 0.5 kb of intron A were identified, most of which transmitted the transgenes to their offspring in a Mendelian pattern. CAT activity was detected predominantly in the lactating mammary gland of female transgenic mice but not in the male mammary fat pad. A several-hundred-fold variation in the level of cat expression was observed in the mammary gland of different lines of mice, presumably due to the site of integration of the transgenes. CAT activity was increased in the mammary gland during development from virgin to midpregnancy and lactation. Unexpectedly, the casein-cat transgenes were also expressed in the thymus of different lines of both male and female mice, in some cases at levels equivalent to those observed in the mammary gland, and in contrast to the mammary gland, CAT activity was decreased during pregnancy and lactation in the thymus. Thus, 0.5 kb of 5'-flanking DNA of the rat beta-casein gene along with noncoding exon I and 0.5 kb of intron A are sufficient to target bacterial cat gene expression to the mammary gland of lactating mice.

Progesterone and EGF inhibit mouse mammary gland prolactin receptor and beta-casein gene expression

1994 ◽  
Vol 267 (5) ◽  
pp. C1467-C1472 ◽  
Author(s):  
S. Nishikawa ◽  
R. C. Moore ◽  
N. Nonomura ◽  
T. Oka
Keyword(s):  
Gene Expression ◽  
Mammary Gland ◽  
Prolactin Receptor ◽  
Mammary Epithelium ◽  
Mouse Mammary Gland ◽  
Mrna Levels ◽  
Casein Gene ◽  
Beta Casein

Regulation of mouse mammary gland long-form prolactin receptor (PRL-RL) mRNA levels by progesterone and epidermal growth factor (EGF) and the relationship between PRL-RL and beta-casein gene expression were examined in vivo and in vitro. PRL-RL and beta-casein mRNA levels increased approximately 6- and 15-fold from the pregnant to the lactating period, respectively, when normalized to the level of beta-actin mRNA. Ovariectomy of pregnant mice rapidly reduced the serum concentration of progesterone and increased the level of PRL-RL and beta-casein mRNAs approximately three- and fourfold compared with sham-operated animals 24 h after the operation. Injection of progesterone, but not estrogen, inhibited the increase in both mRNA levels. PRL-RL and beta-casein mRNA levels in cultured mammary epithelium increased in response to insulin, hydrocortisone, and prolactin, whereas progesterone or EGF caused inhibition. The combination of EGF and progesterone produced a greater inhibition than either hormone alone. These results indicate that both progesterone and EGF serve as negative regulators of lactogenesis.

scholarly journals Two distinct phases of apoptosis in mammary gland involution: proteinase-independent and -dependent pathways

Development ◽  
1996 ◽  
Vol 122 (1) ◽  
pp. 181-193 ◽  
Author(s):  
L.R. Lund ◽  
J. Romer ◽  
N. Thomasset ◽  
H. Solberg ◽  
C. Pyke ◽  
...  
Keyword(s):  
Gene Expression ◽  
Extracellular Matrix ◽  
Mammary Gland ◽  
Epithelial Cells ◽  
Tissue Remodeling ◽  
Apoptotic Cells ◽  
Gelatinase A ◽  
Casein Gene ◽  
Mammary Gland Involution ◽  
Beta Casein

Postlactational involution of the mammary gland is characterized by two distinct physiological events: apoptosis of the secretory, epithelial cells undergoing programmed cell death, and proteolytic degradation of the mammary gland basement membrane. We examined the spatial and temporal patterns of apoptotic cells in relation to those of proteinases during involution of the BALB/c mouse mammary gland. Apoptosis was almost absent during lactation but became evident at day 2 of involution, when beta-casein gene expression was still high. Apoptotic cells were then seen at least up to day 8 of involution, when beta-casein gene expression was being extinguished. Expression of sulfated glycoprotein-2 (SGP-2), interleukin-1 beta converting enzyme (ICE) and tissue inhibitor of metalloproteinases-1 was upregulated at day 2, when apoptotic cells were seen initially. Expression of the matrix metalloproteinases gelatinase A and stromelysin-1 and the serine proteinase urokinase-type plasminogen activator, which was low during lactation, was strongly upregulated in parallel starting at day 4 after weaning, coinciding with start of the collapse of the lobulo-alveolar structures and the intensive tissue remodeling in involution. The major sites of mRNA synthesis for these proteinases were fibroblast-like cells in the periductal stroma and stromal cells surrounding the collapsed alveoli, suggesting that the degradative phase of involution is due to a specialized mesenchymal-epithelial interaction. To elucidate the functional role of these proteinases during involution, at the onset of weaning we treated mice systemically with the glucocorticoid hydrocortisone, which is known to inhibit mammary gland involution. Although the initial wave of apoptotic cells appeared in the lumina of the gland, the dramatic regression and tissue remodeling usually evident by day 5 was substantially inhibited by systemic treatment with hydrocortisone. mRNA and protein for gelatinase A, stromelysin-1 and uPA were weakly induced, if at all, in hydrocortisone-treated mice. Furthermore, mRNA for membrane-type matrix metalloproteinase decreased after hydrocortisone treatment and paralleled the almost complete inhibition of activation of latent gelatinase A. Concomitantly, the gland filled with an overabundance of milk. Our data support the hypothesis that there are at least two distinct phases of involution: an initial phase, characterized by induction of the apoptosis-associated genes SGP-2 and ICE and apoptosis of fully differentiated mammary epithelial cells without visible degradation of the extracellular matrix, and a second phase, characterized by extracellular matrix remodeling and altered mesenchymal-epithelial interactions, followed by apoptosis of cells that are losing differentiated functions.

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