Can direct collapse black holes launch gamma-ray bursts and grow to
  supermassive black holes?
  The existence of black holes (BHs) of mass ~ 10^{9} M_sun at z > 6 is a big
puzzle in astrophysics because even optimistic estimates of the accretion time
are insufficient for stellar mass BHs of ~ 10 M_sun to grow into such
supermassive BHs. A resolution of this puzzle might be the direct collapse of
supermassive stars with mass M ~ 10^{5} M_sun into massive seed BHs. We find
that if a jet is launched from the accretion disk around the central BH, the
jet can break out the star because of the structure of the radiation
pressure-dominated envelope. Such ultra-long gamma-ray bursts with duration of
~ 10^{4} - 10^{6} s and flux of 10^{-11} - 10^{-8} erg s^{-1} cm^{-2} could be
detectable by Swift. We estimate an event rate of < 1yr^{-1}. The total
explosion energy is > 10^{55} - 10^{56} erg. The resulting negative feedback
delays the growth of the remnant BH by about 70 Myr or evacuates the host
galaxy completely.
