title: Human protamine-1 as an MRI reporter gene based on chemical exchange.
abstract: Genetically engineered reporters have revolutionized the understanding of many biological processes. MRI-based reporter genes can dramatically improve our ability to monitor dynamic gene expression and allow coregistration of subcellular genetic information with high-resolution anatomical images. We have developed a biocompatible MRI reporter gene based on a human gene, the human protamine-1 (hPRM1). The arginine-rich hPRM1 (47% arginine residues) generates high MRI contrast based on the chemical exchange saturation transfer (CEST) contrast mechanism. The 51 amino acid-long hPRM1 protein was fully synthesized using microwave-assisted technology, and the CEST characteristics of this protein were compared to other CEST-based contrast agents. Both bacterial and human cells were engineered to express an optimized hPRM1 gene and showed higher CEST contrast compared to controls. Live cells expressing the hPRM1 reporter gene, and embedded in three-dimensional culture, also generated higher CEST contrast compared to wild-type live cells.
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21231, United States.
authors.forename: Amnon
authors.initials: A
authors.lastname: Bar-Shir
authors.forename: Guanshu
authors.initials: G
authors.lastname: Liu
authors.forename: Kannie W Y
authors.initials: KW
authors.lastname: Chan
authors.forename: Nikita
authors.initials: N
authors.lastname: Oskolkov
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Song
authors.forename: Nirbhay N
authors.initials: NN
authors.lastname: Yadav
authors.forename: Piotr
authors.initials: P
authors.lastname: Walczak
authors.forename: Michael T
authors.initials: MT
authors.lastname: McMahon
authors.forename: Peter C M
authors.initials: PC
authors.lastname: van Zijl
authors.forename: Jeff W M
authors.initials: JW
authors.lastname: Bulte
authors.forename: Assaf A
authors.initials: AA
authors.lastname: Gilad
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D003287:Contrast Media / Q000737:chemistry* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D017930:Genes, Reporter; D057809:HEK293 Cells; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011479:Protamines / Q000737:chemistry* / Q000235:genetics*
chemical_list: D003287:Contrast Media; C082073:PRM1 protein, human; D011479:Protamines