what holds the sister chromatids together and attaches them to the spindle fibers
Kinetochore The kinetochore (/kɪˈnɛtəkɔər/, /-ˈniːtəkɔər/) is a protein structure on chromatids where the spindle fibers attach during cell division to pull sister chromatids apart.[1] Their proteins help to hold the sister chromatids together and also play a role in chromosome editing.[2]