DCTN3 encodes dynactin subunit 3, a core component of the dynactin complex that activates the dynein molecular motor for processive transport along microtubules. The protein functions in spindle assembly and cytokinesis, with expression regulated during critical developmental transitions including oocyte maturation and early embryogenesis. DCTN3 plays a documented role in reproductive biology. Aberrant expression of DCTN3 during fertilization is associated with increased embryo aneuploidy and developmental failure, particularly in in vitro matured oocytes, where lower maternal DCTN3 levels reduce developmental competence 1. Expression of DCTN3 and related dynactin genes declines with maternal aging and correlates with increased aneuploidy risk in oocytes 2. In cancer contexts, DCTN3 shows differential associations depending on tumor type. In breast cancer, proteome-wide association analysis identified genetically predicted DCTN3 expression as associated with decreased breast cancer risk 3, and DCTN3 overexpression was independently validated as a marker of lymph node metastatic involvement 4. In low-grade glioma, high DCTN3 mRNA expression correlates with favorable overall survival 5. DCTN3 has also been identified as a transcriptome target in studies of reproductive toxicology and viral pathogenesis 6, 7. In sporadic amyotrophic lateral sclerosis, DCTN3 expression is elevated in peripheral blood mononuclear cells 8.