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Gene expression analysis of protein synthesis pathways in bovine mammary epithelial cells purified from milk during lactation and short‐term restricted feeding
Author(s) -
Sigl T.,
Meyer H. H. D.,
Wiedemann S.
Publication year - 2014
Publication title -
journal of animal physiology and animal nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.651
H-Index - 56
eISSN - 1439-0396
pISSN - 0931-2439
DOI - 10.1111/jpn.12039
Subject(s) - lactation , biology , mammary gland , stat protein , gene expression , janus kinase , signal transduction , enhancer , gene , medicine , microbiology and biotechnology , endocrinology , biochemistry , stat3 , genetics , pregnancy , cancer , breast cancer
Summary The objective of the study was to investigate selected key regulatory pathways of milk protein biosynthesis in primary bovine mammary epithelial cells ( MEC s) 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 H olstein– F riesian 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 E 74‐like factor 5 ( ELF 5 ), an enhancer of signal transducer and activator of transcription ( STAT ) action, concomitantly decreased towards mid‐lactation. Expression of ELF 5 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 ELF 5 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.