  The OVRO 40-m telescope has been monitoring the 15 GHz radio flux density of
over 1200 blazars since 2008. The 15 GHz light curve of the flat spectrum radio
quasar J1359+4011 shows a strong and persistent quasi-periodic oscillation. The
time-scale of the oscillation varies between 120 and 150 days over a $\sim4$
year time span. We interpret this as the active galactic nucleus mass-scaled
analog of low-frequency quasi-periodic oscillations from Galactic microquasars,
or as evidence of modulation of the accretion flow by thermal instabilites in
the "inner" accretion disc.
