1. Gene expression analysis of protein synthesis pathways in bovine mammary epithelial cells purified from milk during lactation and short-term restricted feeding.
- Author
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Sigl, T., Meyer, H. H. D., and Wiedemann, S.
- Subjects
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GENE expression , *PROTEIN synthesis , *EPITHELIAL cells , *LACTATION , *ANIMAL feeding , *PROTEIN metabolism , *POLYMERASE chain reaction - Abstract
The objective of the study was to investigate selected key regulatory pathways of milk protein biosynthesis in primary bovine mammary epithelial cells ( MECs) of dairy cows during the first 155 days of lactation. In addition, cows were exposed to feed restriction for a short period ( FR) during different stages of lactation (week 4 and 21 pp) to study adjustment processes of molecular protein biosynthesis to metabolic challenge. Morning milk samples from twenty-four Holstein- Friesian cows were collected throughout the experimental period ( n = 10 per animal). MEC from raw milk were purified using an immunomagnetic separation technique and used for real-time quantitative PCR analyses. As was seen in transcript abundances of all major milk proteins, m RNA levels of E74-like factor 5 ( ELF5), an enhancer of signal transducer and activator of transcription ( STAT) action, concomitantly decreased towards mid-lactation. Expression of ELF5 as well as of all milk protein genes showed a similar increase during FR in early lactation. Occasional changes in expression could be seen in other Janus kinase ( JAK)/ STAT factors and in mammalian target of rapamycin (m TOR) pathway elements. Amino acid transfer and glucose transporter and the β-casein expression were also partially affected. In conclusion, our findings suggest a pivotal role of the transcription factor ELF5 in milk protein m RNA expression with complementary JAK/ STAT and m TOR signalling for the regulation of protein biosynthesis in the bovine mammary gland. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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