CHICKEN OOCYTE GROWTH IS MEDIATED BY AN 8 LIGAND-BINDING REPEAT MEMBER OF THE LDL RECEPTOR FAMILY
CHICKEN OOCYTE GROWTH IS MEDIATED BY AN 8 LIGAND-BINDING REPEAT MEMBER OF THE LDL RECEPTOR FAMILY
复制标题
DOI：
10.1002/j.1460-2075.1994.tb06847.x
复制
发表时间：
1994-11-01
期刊：
影响因子：
11.4
通讯作者：
SCHNEIDER, WJ
中科院分区：
文献类型：
--
作者：
BUJO, H;HERMANN, M;SCHNEIDER, WJ
鸡卵母细胞的卵黄质量成分、极低密度脂蛋白 (VLDL) 和卵黄蛋白原 (VTG) 的沉积是由 95 kDa 质膜蛋白（称为 VLD/NTG 受体 (VLDL/VTGR)）介导的。 VLDL/VTGR 的分子特征表明，它是 LDLR 基因超家族的成员，并在 N 末端具有八个补体型、富含半胱氨酸的配体结合重复序列。这种配体结合域结构是最近发现的哺乳动物所谓的 VLDLR 的标志，其真正的生理功能已被阐明。 Northern 印迹分析表明，该受体几乎只在卵母细胞中表达，而心脏和骨骼肌中存在的杂交转录物水平要低得多。克隆受体的异源表达证明了其结合 VLDL 和 VTG 的能力。该受体基因位于鸟类性染色体Z上，与由于缺乏功能性VLDL/VTGR表达而无法繁殖的动物中单基因缺陷的性别连锁一致。卵母细胞的原位杂交分析表明，VLDL/VTGR mRNA 可能在卵母细胞生长过程中重新定位。因此，当前的研究已经鉴定并表征了第一个非哺乳动物 VLDLR。它在鸟类繁殖中的关键作用和极高的进化保守性为哺乳动物中的 VLDLR 功能提供了新的线索，哺乳动物也在卵巢中表达该基因。
Deposition of the yolk mass components of chicken oocytes, very low density lipoprotein (VLDL) and vitellogenin (VTG), is mediated by a 95 kDa plasma membrane protein, termed VLD/NTG receptor (VLDL/VTGR). Molecular characterization of the VLDL/VTGR revealed that it is a member of the LDLR gene superfamily, and harbours eight complement-type, cysteine-rich ligand binding repeats at the N-terminus. This ligand binding domain structure is the hallmark of the recently discovered mammalian so-called VLDLRs, whose true physiological function be elucidated. Northern blot analysis that this receptor is expressed almost exclusively in oocytes, with very much lower levels of hybridizing transcripts present in heart and skeletal muscle. Heterologous expression of the cloned receptor demonstrated its ability to bind both VLDL and VTG. The receptor gene is located on the avian sex chromesome Z, in agreement with the sex linkage of a single-gene defect in animals that fail to reproduce because of the lack of expression of functional VLDL/VTGR. In situ hybridization analysis of oocytes suggested that VLDL/VTGR mRNA may relocalize during oocyte growth. Thus, the current study has identified and characterized the first non-mammalian VLDLR. Its key role in avian reproduction and extremely high evolutionary conservation shed new light on VLDLR function in mammals, which also express the gene in ovaries.