Gene networks driving bovine milk fat synthesis during the lactation cycle

A network of genes participates in coordinating milk fat synthesis and secretion. Results challenge the proposal that SREBF1 is central for milk fat synthesis regulation and highlight a pivotal role for a concerted action among PPARG, PPARGC1A, and INSIG1. Expression of SCD, the most abundant gene measured, appears to be key during milk fat synthesis. The lack of correlation between gene expression and calculated desaturase indexes does not support their use to infer mRNA expression or enzyme activity (e.g., SCD). Longitudinal mRNA expression allowed development of transcriptional regulation networks and an updated model of milk fat synthesis regulation.