Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, People's Republic of China.
BMC Genomics. 2012 May 30;13:213. doi: 10.1186/1471-2164-13-213.
Intramuscular fat (IMF) is one of the important factors influencing meat quality, however, for chickens, the molecular regulatory mechanisms underlying this trait have not yet been determined. In this study, a systematic identification of candidate genes and new pathways related to IMF deposition in chicken breast tissue has been made using gene expression profiles of two distinct breeds: Beijing-you (BJY), a slow-growing Chinese breed possessing high meat quality and Arbor Acres (AA), a commercial fast-growing broiler line.
Agilent cDNA microarray analyses were conducted to determine gene expression profiles of breast muscle sampled at different developmental stages of BJY and AA chickens. Relative to d 1 when there is no detectable IMF, breast muscle at d 21, d 42, d 90 and d 120 (only for BJY) contained 1310 differentially expressed genes (DEGs) in BJY and 1080 DEGs in AA. Of these, 34-70 DEGs related to lipid metabolism or muscle development processes were examined further in each breed based on Gene Ontology (GO) analysis. The expression of several DEGs was correlated, positively or negatively, with the changing patterns of lipid content or breast weight across the ages sampled, indicating that those genes may play key roles in these developmental processes. In addition, based on KEGG pathway analysis of DEGs in both BJY and AA chickens, it was found that in addition to pathways affecting lipid metabolism (pathways for MAPK & PPAR signaling), cell junction-related pathways (tight junction, ECM-receptor interaction, focal adhesion, regulation of actin cytoskeleton), which play a prominent role in maintaining the integrity of tissues, could contribute to the IMF deposition.
The results of this study identified potential candidate genes associated with chicken IMF deposition and imply that IMF deposition in chicken breast muscle is regulated and mediated not only by genes and pathways related to lipid metabolism and muscle development, but also by others involved in cell junctions. These findings establish the groundwork and provide new clues for deciphering the molecular mechanisms underlying IMF deposition in poultry. Further studies at the translational and posttranslational level are now required to validate the genes and pathways identified here.
肌内脂肪（IMF）是影响肉质的重要因素之一，然而，对于鸡来说，这种特性的分子调控机制尚未确定。在这项研究中，使用两个不同品种的基因表达谱，对鸡胸脯组织中与 IMF 沉积相关的候选基因和新途径进行了系统的鉴定：北京油鸡（BJY），一种生长缓慢但肉质优良的中国品种；阿伯丁-安格斯（AA），一种商业性的快速生长肉鸡品种。
使用安捷伦 cDNA 微阵列分析，对不同发育阶段的 BJY 和 AA 鸡胸脯肌肉进行了基因表达谱的测定。与无 IMF 可检测的 d1 相比，BJY 的 d21、d42、d90 和 d120（仅 BJY 有）含有 1310 个差异表达基因（DEGs），AA 含有 1080 个 DEGs。其中，根据基因本体论（GO）分析，对每个品种与脂质代谢或肌肉发育过程相关的 34-70 个 DEGs 进行了进一步研究。这些基因的表达与脂质含量或乳房重量随年龄变化的模式呈正相关或负相关，表明这些基因可能在这些发育过程中发挥关键作用。此外，根据 BJY 和 AA 鸡 DEGs 的 KEGG 途径分析，发现除了影响脂质代谢的途径（MAPK 和 PPAR 信号途径）外，细胞连接相关途径（紧密连接、ECM-受体相互作用、焦点黏附、肌动蛋白细胞骨架调节）也可能对 IMF 沉积有贡献，因为这些途径在维持组织完整性方面发挥着重要作用。
本研究鉴定了与鸡 IMF 沉积相关的潜在候选基因，表明鸡胸脯肌肉中的 IMF 沉积不仅受到与脂质代谢和肌肉发育相关的基因和途径的调控和介导，还受到其他参与细胞连接的基因和途径的调控和介导。这些发现为解析家禽 IMF 沉积的分子机制奠定了基础，并提供了新的线索。目前需要在翻译后和翻译后水平进行进一步的研究，以验证这里鉴定的基因和途径。
