• Equilibrative nucleoside transporter 2 (ENT2), also designated solute carrier family 29 (nucleoside transporters), member 2, belongs to the SLC29A transporter family and is a mammalian ENT isoform. ENT2 mediates the equilibrative transport of hypoxanthine in addition to nucleosides and is purine-selective.
• Equilibrative nucleoside transporters (ENTs) regulate many physiological processes and are widely distributed in mammals, plants, yeasts, insects, nematodes and protozoans. They enable facilitated diffusion of hydrophilic nucleosides, such as adenosine and nucleoside analogs, across cell membranes. ENTs are required for uptake of antiviral and anticancer nucleoside drugs and influence a variety of physiological processes, such as neurotransmission and platelet aggregation, by regulating the amount of adenoside available to cell surface receptors.

Gene targeting strategy for B-hSLC29A2 mice. The exons 3-12 of mouse Slc29a2 gene that encode the whole molecule (ATG to STOP codon), including 3’UTR were replaced by human counterparts in B-hSLC29A2 mice. The promoter and 5’UTR region of the mouse gene are retained. The human SLC29A2 expression is driven by endogenous mouse Slc29a2 promoter, while mouse Slc29a2 gene transcription and translation will be disrupted.

Western blot analysis of SLC29A2 protein expression in homozygous B-hSLC29A2 mice. Various tissue lysates were collected from wild-type C57BL/6N mice (+/+) and homozygous B-hSLC29A2 mice (H/H), and then analyzed by western blot with anti-SLC29A2 antibody (Abcam, ab181192). 40 μg total proteins were loaded for western blotting analysis. SLC29A2 was detected in brain, lung and liver in wild-type mice and homozygous B-hSLC29A2 mice, as the antibody is cross-recognize between human and mouse SLC29A2.

The arrow above indicates the glycosylated SLC29A2 protein.

Strain specific analysis of SLC29A2 mRNA expression in wild-type C57BL/6N mice and homozygous B-hSLC29A2 mice by RT-PCR. Brain RNA was isolated from wild-type C57BL/6N mice (+/+) and homozygous B-hSLC29A2 mice (H/H). Mouse Slc29a2 mRNA was detectable only in wild-type mice. Human SLC29A2 mRNA was detectable only in B-hSLC29A2 mice but not in wild-type mice.