TY - JOUR
T1 - Genetic demonstration that the mutationally expressed nucleobase transporter of mouse S49 cells is nonconcentrative
AU - Beck, Joanne
AU - Ullman, Buddy
N1 - Funding Information:
This researchw as supportedb y Grant DK 38809f rom the National Instituteso f Health. J.B. was supportedi n part by a Tartar Medical Foundation Fellowship. B. U. is a recipient of a National Instituteso f Health Career DevelopmentA ward.
PY - 1987/7
Y1 - 1987/7
N2 - Somatic cell genetic analysis of purine base transporters in mouse S49 cells has demonstrated the existence of a unique high-affinity purine base transporter, which is mutationally expressed and is not found in wild-type S49 cells or any other cells of the animal kingdom (B. Aronow, et al. (1986) Mol. Cell. Biol.6, 2957). In order to determine whether this nucleobase transport system is active and concentrative, a secondary mutation in hypoxanthine-guanine phosphoribosyltransferase (HGPRTase) was inserted into the cell line expressing this novel base transporter. The HGPRTase-deficient cells were capable of transporting hypoxanthine at increased rates but did not accumulate the base to concentrations in excess of that in the culture medium. Moreover, neither sodium azide nor ouabain had significant effects on hypoxanthine transport rates, indicating that energy metabolism and the maintenance of a sodium gradient were not required for transport function. These studies suggest that the novel mutationally expressed base transporter is independent of subsequent metabolism and does not require energy or a functioning Na+-K+-dependent ATPase activity.
AB - Somatic cell genetic analysis of purine base transporters in mouse S49 cells has demonstrated the existence of a unique high-affinity purine base transporter, which is mutationally expressed and is not found in wild-type S49 cells or any other cells of the animal kingdom (B. Aronow, et al. (1986) Mol. Cell. Biol.6, 2957). In order to determine whether this nucleobase transport system is active and concentrative, a secondary mutation in hypoxanthine-guanine phosphoribosyltransferase (HGPRTase) was inserted into the cell line expressing this novel base transporter. The HGPRTase-deficient cells were capable of transporting hypoxanthine at increased rates but did not accumulate the base to concentrations in excess of that in the culture medium. Moreover, neither sodium azide nor ouabain had significant effects on hypoxanthine transport rates, indicating that energy metabolism and the maintenance of a sodium gradient were not required for transport function. These studies suggest that the novel mutationally expressed base transporter is independent of subsequent metabolism and does not require energy or a functioning Na+-K+-dependent ATPase activity.
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U2 - 10.1016/0014-4827(87)90269-2
DO - 10.1016/0014-4827(87)90269-2
M3 - Article
C2 - 3622635
AN - SCOPUS:0023638679
SN - 0014-4827
VL - 171
SP - 254
EP - 258
JO - Experimental Cell Research
JF - Experimental Cell Research
IS - 1
ER -