Transcription factor E2F4 is a positive regulator of milk biosynthesis and proliferation of bovine mammary epithelial cells

Abstract

The transcription factor E2F4 is a key determinant of cell differentiation and cell‐cycle progression, but its function and regulatory mechanism are not completely understood. Here, we report that E2F4 acts as a positive regulator of the biosynthesis of milk components and proliferation of bovine mammary epithelial cells (BMECs). Overexpression of E2F4 in BMECs resulted in the upregulation of β‐casein, triglyceride, and lactose levels and increased cell proliferation, whereas E2F4 knockdown by small interfering RNA had the opposite effects. We further detected that overexpression of E2F4 significantly increased the messenger RNA expression of mTOR, SREBP‐1c, and Cyclin D1, and increased protein levels of SREBP‐1c, and Cyclin D1, and the ratio of p‐mTOR/mTOR, whereas E2F4 knockdown had the opposite effects. E2F4 was almost entirely located in the nucleus, and we further identified, via ChIP‐qPCR analysis, that mTOR, SREBP‐1c, and Cyclin D1 were E2F4 target genes, and exogenous administration of methionine, leucine, β‐estradiol, and prolactin markedly increased the protein levels of E2F4 and its binding to the promoters of these three genes. In summary, our data reveal that E2F4 responds to extracellular stimuli and regulates the expression of mTOR, SREBP‐1c, and Cyclin D1 for milk biosynthesis and proliferation of BMECs.

Optimizing hormonal and amino acid combinations for enhanced cell proliferation and cell cycle progression in bovine mammary epithelial cells

“…Consistent with this study, the peptide hormone (kisspeptin-10) and optimal EAAs had resulted in higher cell viability with an increase in S and G2/M phases compared to that of control cells in BMECs [14,43]. In addition, previous studies have reported that the increase in the S and G2/M phases during the progression of the cell cycle promotes cell proliferation along with an increase in PCNA and cyclin B1 levels in BMECs and mouse mesenchymal stem cells [44][45][46]. Moreover, our data showed that H-and HAtreated cells had higher DAPI-stained areas, thereby indicating an increase in cell proliferation and cell numbers compared to that in control cells (Figure 6).…”

A functional mutation associated with piglet diarrhea partially by regulating the transcription of porcine STAT3

“…Both E2F4 and E2F6 belong to the ubiquitous E2F family of transcription factors which control cell proliferation and terminal fate (38)(39)(40). E2F4 was initially categorized as the major repressor of cell cycle progressions, however, recent research showed that E2F4 acted in part as a transcriptional activator that promoted the expression of cell cycle genes in mouse embryonic stem cells (41), functioned as a positive regulator of milk biosynthesis and proliferation of bovine mammary epithelial cells (42) and it could positively regulate hepatitis B virus (HBV)transcription by binding the core promoter of HBV covalently closed circular DNA (43). In this study, the positive regulation of E2F4 on G allele supported the point that E2F4 regulated diverse gene expression programs in cell fate decisions (44).…”

E2F4DN Transgenic Mice: A Tool for the Evaluation of E2F4 as a Therapeutic Target in Neuropathology and Brain Aging

“…Indeed, under growth arrest conditions, E2F4 can repress a common set of genes involved in mitochondrial biogenesis and metabolism [ 66 ]. Moreover, E2F4 participates in the differentiation of multiple cell types, including the differentiation of myocytes [ 22 , 36 , 67 , 68 , 69 ], neural cells [ 30 , 70 ], adipocytes [ 71 , 72 , 73 , 74 ], hematopoietic cells [ 75 ], chondrocytes [ 76 ], extra-embryonic tissues [ 77 ], endothelial cells [ 78 ], epithelial cells [ 79 ], and multiciliated cells [ 80 , 81 ]. E2F4 can also regulate eye and brain patterning [ 82 , 83 , 84 , 85 ], as well as endocytosis and water channel transport in the testes [ 81 ].…”