Fig.1 Resuscitation culture of BMECs A, BMECs after 24 h of resuscitation culture, the green arrow points to the secreted milk droplet; B, BMECs after 3 d of resuscitation culture, with green arrows pointing to the bulge after cell contact.

Fig.2 Results of total RNA extraction from different tissues and BMECs of dairy cow A, 1-7 are the results of total RNA extraction from the small intestine, liver, kidney, uterus, heart, ovary and mammary gland of cow, respectively; B, 1 and 2 are the results of total RNA extraction from BMECs. M is DL 2000 DNA marker.

Fig.3 Stability of different internal reference genes A, Standard deviation and coefficient of variation of Cq values of different internal reference genes; B, Cq values of different internal reference genes.

Fig.4 Relative expression levels of candidate differential genes of milk fat metabolism in different tissues of dairy cow The bars marked without the same lowercase letter indicated significant differences at P<0.05. The same as below.

Fig.5 The expression differences of candidate differential genes of milk fat metabolism in mammary gland (A) and BMECs (B) * represented significant difference compared with other genes.

Fig.6 Schematic diagram of the structure of bovine PI4K2A gene

Fig.7 Cloning of PI4K2A gene A, Results of PCR amplification of CDS region of PI4K2A gene, 1 and 2 are amplification products; B, Results of amplification product recovery and purification, 1 and 2 are recovered products; C, Results of bacteria amplification of PI4K2A gene, 1-8 are amplification products. M is DL2000 DNA marker.

Fig.8 Amino acid composition of PI4K2A protein

Fig.9 Function prediction of PI4K2A protein A, Hydrophobicity/hydrophilicity prediction; B, Signal peptide prediction; C, Transmembrane structure prediction; D, Phosphorylation site prediction.

Fig.10 Total RNA extraction from nucleus and plasma of BMECs and subcellular localization of PI4K2A mRNA A, Results of nuclear and plasma total RNA extraction from BMECs; B, The distribution of PI4K2A in BMECs.

Fig.11 Phylogenetic tree analysis of PI4K2A proteins of different species

Fig.12 Similarity analysis of the spatial structure of PI4K2A protein in different species Red arrows indicate the locations where the spatial structure of PI4K2A protein changes in other species relative to that of cattle.