Tannous Bakhos A, Grimm Jan, Perry Katherine F, Chen John W, Weissleder Ralph, Breakefield Xandra O
Center for Molecular Imaging Research, Massachusetts General Hospital-East, Building 149, 13th Street, Charlestown, Massachusetts 02129, USA.
Nat Methods. 2006 May;3(5):391-6. doi: 10.1038/nmeth875.
We have developed a versatile, potent technique for imaging cells in culture and in vivo by expressing a metabolically biotinylated cell-surface receptor and visualizing it with labeled streptavidin moieties. The recombinant reporter protein, which incorporates a biotin acceptor peptide (BAP) between an N-terminal signal sequence and a transmembrane domain, (BAP-TM) was efficiently biotinylated by endogenous biotin ligase in mammalian cells with the biotin displayed on the cell surface. Tumors expressing the BAP-TM have high sensitivity for magnetic resonance and fluorescence tomographic imaging in vivo after intravascular injection of streptavidin conjugated to magnetic nanoparticles or fluorochromes, respectively. Moreover, streptavidin-horseradish peroxidase conjugates in conjunction with a peroxidase-sensitive gadolinium agent further increased and prolonged the magnetic resonance signal. This BAP-TM allows noninvasive real-time imaging of any cell type transduced to express this reporter protein in culture or in vivo.
我们开发了一种通用且高效的技术，通过表达一种经代谢生物素化的细胞表面受体并用标记的链霉亲和素部分对其进行可视化，从而对培养中的细胞和体内细胞进行成像。这种重组报告蛋白在N端信号序列和跨膜结构域之间包含一个生物素接受肽（BAP），即（BAP-TM），它在哺乳动物细胞中被内源性生物素连接酶有效地生物素化，生物素展示在细胞表面。表达BAP-TM的肿瘤在分别向血管内注射与磁性纳米颗粒或荧光染料偶联的链霉亲和素后，对体内磁共振和荧光断层成像具有高灵敏度。此外，链霉亲和素-辣根过氧化物酶偶联物与过氧化物酶敏感的钆剂相结合，进一步增强并延长了磁共振信号。这种BAP-TM能够对在培养中或体内转导以表达这种报告蛋白的任何细胞类型进行无创实时成像。
