TitleOld and new stories: revelations from functional analysis of the bovine mammary transcriptome during the lactation cycle.
Publication TypeJournal Article
Year of Publication2012
AuthorsBionaz, M, Periasamy, K, Rodriguez-Zas, SL, Everts, RE, Lewin, HA, Hurley, WL, Loor, JJ
JournalPLoS One
Volume7
Issue3
Paginatione33268
Date Published2012
ISSN1932-6203
KeywordsAnimals, Cattle, Female, Galactose, Gene Expression Profiling, Glycosylphosphatidylinositols, Lactation, Mammary Glands, Animal, Microarray Analysis, Peroxisome Proliferator-Activated Receptors, Time Factors, Transcriptome
Abstract

The cow mammary transcriptome was explored at -30, -15, 1, 15, 30, 60, 120, 240, and 300 d relative to parturition. A total of 6,382 differentially expressed genes (DEG) at a false discovery rate ≤ 0.001 were found throughout lactation. The greatest number of DEG (>3,500 DEG) was observed at 60 and 120 d vs. -30 d with the largest change between consecutive time points observed at -15 vs. 1 d and 120 vs. 240 d. Functional analysis of microarray data was performed using the Dynamic Impact Approach (DIA). The DIA analysis of KEGG pathways uncovered as the most impacted and induced 'Galactose metabolism', 'Glycosylphosphatidylinositol (GPI)-anchor biosynthesis', and 'PPAR signaling'; whereas, 'Antigen processing and presentation' was among the most inhibited. The integrated interpretation of the results suggested an overall increase in metabolism during lactation, particularly synthesis of carbohydrates and lipid. A marked degree of utilization of amino acids as energy source, an increase of protein export, and a decrease of the protein synthesis machinery as well cell cycle also were suggested by the DIA analysis. The DIA analysis of Gene Ontology and other databases uncovered an induction of Golgi apparatus and angiogenesis, and the inhibition of both immune cell activity/migration and chromosome modifications during lactation. All of the highly-impacted and activated functions during lactation were evidently activated at the onset of lactation and inhibited when milk production declined. The overall analysis indicated that the bovine mammary gland relies heavily on a coordinated transcriptional regulation to begin and end lactation. The functional analysis using DIA underscored the importance of genes associated with lactose synthesis, lipid metabolism, protein synthesis, Golgi, transport, cell cycle/death, epigenetic regulation, angiogenesis, and immune function during lactation.

DOI10.1371/journal.pone.0033268
Alternate JournalPLoS ONE
PubMed ID22428004
PubMed Central IDPMC3299771
Grant ListR01 GM068946 / GM / NIGMS NIH HHS / United States