Meiosis plasmid segregation in ndj1Δ and csm4Δ strains: A model for 2 micron plasmid segregation during meiosis I. The segregation analyses were performed using the STB reporter plasmid, as described under Fig. 1. The bar graphs showing the types of plasmid segregation during meiosis I (A) represent the analysis of 75–100 cells. Wild-type values are from Fig. 1 C. The n:∼n class includes n:n and n:n − 1. Segregation results for a chromosome, fluorescence-tagged at CEN on both homologues, are given in Fig. S5. (B) A model embodying current results envisages the 2 micron plasmid as gaining access to the nuclear envelope-associated motor machinery with the assistance of the Rep1-Rep2-STB system. Ndj1 appears not to be essential for plasmid–membrane association, although it may enhance plasmid tethering to TELs as they become anchored at the envelope and engage the motor. An alternative membrane-independent interaction of plasmids with TELs (shown by the broken lines) cannot be ruled out. Csm4, the force transducer of the motor, may be related to KASH domain proteins (Koszul and Kleckner, 2009). TEL-associated plasmid segregation during meiosis I would be consistent with potential hitchhiking of plasmids on chromosomes during mitosis (Velmurugan et al., 2000; Mehta et al., 2002; Liu et al., 2013). Current evidence does not preclude meiotic plasmid segregation in a membrane-associated fashion independent of chromosomes. Furthermore, the TEL-associated and chromosome-independent pathways of plasmid segregation need not be mutually exclusive. The representations of Csm4 and Mps3 here are patterned after those from an earlier review (Starr and Fridolfsson, 2010).