Animal Science Department and.
Annu Rev Anim Biosci. 2014 Feb;2:323-51. doi: 10.1146/annurev-animal-022513-114211.
Early in porcine adipose tissue development, the stromal-vascular (SV) elements control and dictate the extent of adipogenesis in a depot-dependent manner. The vasculature and collagen matrix differentiate before overt adipocyte differentiation. In the fetal pig, subcutaneous (SQ) layer development is predictive of adipocyte development, as the outer, middle, and inner layers of dorsal SQ adipose tissue develop and maintain layered morphology throughout postnatal growth of SQ adipose tissue. Bovine and ovine fetuses contain brown adipose tissue but SQ white adipose tissue is poorly developed structurally. Fetal adipose tissue differentiation is associated with the precocious expression of several genes encoding secreted factors and key transcription factors like peroxisome proliferator activated receptor (PPAR)γ and CCAAT/-enhancer-binding protein. Identification of adipocyte-associated genes differentially expressed by age, depot, and species in vivo and in vitro has been achieved using single-gene analysis, microarrays, suppressive subtraction hybridization, and next-generation sequencing applications. Gene polymorphisms in PPARγ, cathepsins, and uncoupling protein 3 have been associated with back fat accumulation. Genome scans have mapped several quantitative trait loci (QTL) predictive of adipose tissue-deposition phenotypes in cattle and pigs.
在猪脂肪组织发育的早期，基质血管（SV）成分以依赖于脂肪库的方式控制和决定脂肪生成的程度。血管和胶原基质在明显的脂肪细胞分化之前分化。在胎儿猪中，皮下（SQ）层的发育可预测脂肪细胞的发育，因为背侧 SQ 脂肪组织的外层、中层和内层发育并在 SQ 脂肪组织的整个出生后生长过程中保持分层形态。牛和羊胎儿含有棕色脂肪组织，但 SQ 白色脂肪组织在结构上发育不良。脂肪组织的分化与几个编码分泌因子和关键转录因子（如过氧化物酶体增殖物激活受体（PPAR）γ和CCAAT/-增强子结合蛋白）的基因的过早表达有关。使用单基因分析、微阵列、抑制性消减杂交和下一代测序应用，已经实现了体内和体外通过年龄、脂肪库和物种差异表达的脂肪细胞相关基因的鉴定。PPARγ、组织蛋白酶和解偶联蛋白 3 的基因多态性与背脂积累有关。基因组扫描已经绘制了预测牛和猪脂肪组织沉积表型的几个数量性状位点（QTL）图谱。
