Savon S, Hakimi P, Hanson R W
Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935.
Biol Neonate. 1993;64(1):62-8. doi: 10.1159/000243972.
Gluconeogenesis in the chicken has unique features due in part to the presence of two isozymes of PEPCK, a cytosolic form, PEPCK-C, and a mitochondrial form, PEPCK-M, which have novel patterns of expression. Here we show that, in contrast to mammals, in which PEPCK-C is not present in liver until after birth, avian PEPCK-C is expressed throughout embryonic life with mRNA levels gradually decreasing as development proceeds and becoming negligible at time of hatching. In addition two distinct mRNAs for PEPCK-M are expressed during development with specific patterns that vary among individual birds. These differences are likely to be genetic, as hormonal treatment of a chicken hepatoma cell line indicates that whereas the mRNA levels for PEPCK-C are hormonally regulated, the expression of PEPCK-M mRNA is unresponsive.
鸡的糖异生具有独特特征，部分原因在于存在磷酸烯醇式丙酮酸羧激酶（PEPCK）的两种同工酶，一种是胞质形式的PEPCK - C，另一种是线粒体形式的PEPCK - M，它们具有新的表达模式。我们在此表明，与哺乳动物不同，哺乳动物出生后肝脏中才出现PEPCK - C，而禽类的PEPCK - C在整个胚胎期均有表达，随着发育进程，其mRNA水平逐渐降低，在孵化时变得微不足道。此外，在发育过程中表达了两种不同的PEPCK - M mRNA，其特定模式在个体鸟类之间有所不同。这些差异可能是遗传性的，因为对鸡肝癌细胞系进行激素处理表明，虽然PEPCK - C的mRNA水平受激素调节，但PEPCK - M mRNA的表达无反应。
