This line is called the spindle equator.

Spindle fibers bind to the centromeres of each pair of homologs and arrange the pairs at the spindle equator.

Dynein is released from kinetochores as they acquire kMTs and, in cultured mammalian cells, it is required for the spindle checkpoint inactivation, but not for chromosome congression in the spindle equator, kMTs acquisition or anaphase A during chromosome segregation.