May function as a proton-driven pyrimidine uptake system. Up-regulated by the nitrogen regulatory protein C (NtrC also called GlnG) and repressed by RutR. Cells lacking this gene fail to grow on the nucleobase uracil as the sole nitrogen source but use the nucleoside uridine normally. The Rut pathway degrades exogenous pyrimidines as the sole nitrogen source at room temperature but not at 37 degrees Celsius, a restriction that is apparently a consequence of an inadequate ability to remove toxic malonic semialdehyde at the higher temperature (RutE/YdfG function). Belongs to the nucleobase:cation symporter-2 (NCS2) (TC 2.A.40) family.