Webb N R, de Villiers W J, Connell P M, de Beer F C, van der Westhuyzen D R
Department of Internal Medicine, University of Kentucky Medical Center, Lexington 40536, USA.
J Lipid Res. 1997 Jul;38(7):1490-5.
The class B, type I scavenger receptor has been implicated as a receptor for high density lipoprotein (HDL). We have isolated a murine cDNA clone encoding an alternative form of SR-BI that differs in the putative cytoplasmic domain of the receptor. This variant form, likely the result of alternative mRNA splicing, is designated SR-BI.2. SR-BI.2 mRNA was detected in mouse tissues known to express SR-BI and tissue-specific differences in the relative abundance of SR-BI.2 were apparent. In mouse adrenal glands, SR-BI.2 represented approximately one-third of total SR-BI mRNA, whereas in mouse testes, SR-BI.2 represented the major mRNA species (79% of total). SR-BI.2 was also detected in the human cell lines examined, namely HeLa, HepG2, and THP-1 cells. CHO cells transfected with the mouse SR-BI.2 cDNA expressed significant levels of SR-BI.2 protein and acquired the ability to take up fluorescent lipid (DiI) from DiI-HDL. Alternative splicing of SR-BI represents a potentially important process for the regulation of SR-BI expression and function.
B类I型清道夫受体被认为是高密度脂蛋白（HDL）的受体。我们分离出了一个小鼠cDNA克隆，它编码SR-BI的一种变体形式，该变体在受体假定的胞质结构域有所不同。这种变体形式可能是mRNA可变剪接的结果，被命名为SR-BI.2。在已知表达SR-BI的小鼠组织中检测到了SR-BI.2 mRNA，并且SR-BI.2相对丰度存在组织特异性差异。在小鼠肾上腺中，SR-BI.2约占SR-BI总mRNA的三分之一，而在小鼠睾丸中，SR-BI.2是主要的mRNA种类（占总量的79%）。在所检测的人类细胞系，即HeLa、HepG2和THP-1细胞中也检测到了SR-BI.2。用小鼠SR-BI.2 cDNA转染的CHO细胞表达了高水平的SR-BI.2蛋白，并获得了从DiI-HDL摄取荧光脂质（DiI）的能力。SR-BI的可变剪接代表了SR-BI表达和功能调控的一个潜在重要过程。
