Casein Gene Expression in Bovine Mammary Gland

Abstract

Bovine casein gene cluster belongs to the best studied regions of the bovine genome. However, molecular basis of the regulation of casein gene expression is still of great interest for the advancement of milk production. Identification of crucial regulatory regions governing casein gene expression would provide valuable information for marker assisted selection in dairy cattle. In our study we performed comparative analysis of the bovine beta-and kappa casein gene promoter sequences with the regulatory sequences from some other species. In addition, we used homologous mammary gland derived cell culture and luciferase reporter gene system to confirm the functionality of the proximal beta and kappa casein promoters. The longer kappa casein promoter (2064 bp) showed the highest expression level, followed by the short kappa casein promoter (925 bp) and beta casein promoter (1692 bp). Here we demonstrate the suitability of the bovine mammary gland derived cell line BME UV1 for transient gene expression under transcriptional control of the bovine casein gene promoters and compare functionality of different fragments of bovine beta-and kappa casein gene promoters using homologous in vitro system. Zusammenfassung Titel der Arbeit: Funktionsanalyse der Rinder β-und κ-Kaseingenpromotoren mit Hilfe der homologen Euterzelllinie Kasein Gen Cluster beim Rind gehören zu den am besten untersuchten Teilen des Rindergenoms. Trotzdem herrscht noch immer groβes Interesse an detaillierten Studien über die molekulare Basis der Regulation der Kaseingen-Expression zur Steigerung der Milchproduktion. Die Entdeckung der Hauptregulationsmechanismen der Kaseingen-Expression wäre von groβer Bedeutung für die markergestützte Selektion der Milchkühe. In unserer Studie haben wir die Promotorsequenzen der Rinder beta-und kappa-Kaseingene im Vergleich zu einigen anderen Säugetierarten untersucht. Die Rinder-Euterzellen BME UV1 und das Luziferase Reportergen System wurden für die Bestätigung der Funktionalität der Rinder β-und κ-Kaseingenpromoters in vitro eingesetzt. Der längere κ-Kaseingen Promoter (2064 bp) hat die stärkste Expression gezeigt, gefolgt von dem kurzen κ-Kaseingen Promoter (925 bp) und dem β-Kaseingen Promoter (1692 bp). Hier können wir demonstrieren, dass die Rindereuterzelllinie BME UV1 für die vorübergehende Genexpression unter der Kontrolle der Rinderkaseingenpromotoren geeignet ist. Die Funktion von verschiedenen Teilen der Rinder β− und κ-Kaseingenpromotern wurde in einem homologen in vitro System verglichen.

In vivo inhibition followed by exogenous supplementation demonstrates galactopoietic effects of prolactin on mammary tissue and milk production in dairy cows

“…The downregulation of milk protein gene expression with QN treatment was previously observed in bovine mammary tissue and in milk-purified MEC (Boutinaud et al, 2012). The effect of QN on milk protein transcripts could be due to the inhibition of milking-induced PRL release, because PRL is known to stimulate milk protein expression in bovine MEC (Choi et al, 1988;Stiening et al, 2008).…”

“…Once activated, STAT5 translocates to the nucleus and binds to specific regulatory sites in the promoters of target genes such as milk protein genes (Groner and Gouilleux, 1995). Also in primary bovine MEC cultures, PRL has been shown to upregulate the mRNA levels of several caseins (Choi et al, 1988). A high number of other genes are under the control of PRL stimulation, as has been shown in bovine MEC using microarray analyses (Stiening et al, 2008;Riley et al, 2010).…”

Effect of casein genes - beta-LGB, DGAT1, GH, and LHR - on milk production and milk composition traits in crossbred Holsteins

“…With regard to the beta + kappacasein genes, both were located very closely within 250 kilobases on chromosome 6 (Bonfatti et al, 2010), so it is possible that both genes have a co-regulation mechanism (Bonfatti et al, 2010), which would explain the association between these genes. A dominant effect of the beta-casein gene was observed, as the composition of milk protein and the proportion of the beta-casein protein (30%) was higher than for the kappa-casein protein (10%) (Choi et al, 1988). Therefore, the effect of the beta-casein gene may be stronger than for the other genes.…”

Regulation of apoptosis and functional activity in bovine mammary Acini

“…The milk protein secretion and the rate of amino acid uptake in mammary acinar cells shown in Table 1 TNF a was about 2 fold higher than that of the counterpart cells in the presence of TNF a (100 ng/ml). The decrease of protein secretion in lactating acinar cells treated with TNF a implies reduced functional activity and casein production in mammary cells (Choi et al, 1988). Amino acid uptake in mammary acini in the presence of TNF a (10 ng/ml) was also significantly decreased by 50%.…”