High impact information on SMC4

• Here we show that MIX-1 interacts with a mitotic condensin subunit, SMC-4, to achieve chromosome segregation [1].
• SMC-4 and MIX-1 colocalize with centromere proteins on condensed mitotic chromosomes and are required for the restricted orientation of centromeres toward spindle poles [1].
• Depletion of SMC-4/MIX-1 causes aberrant mitotic chromosome structure and segregation, but not dramatic decondensation at metaphase [1].
• Cnd1, Cnd2, and Cnd3, three non-SMC subunits showing a high degree of sequence conservation to frog subunits, are essential for viability, and their gene disruption leads to a phenotype indistinguishable from that observed in cut3-477 and cut14-208, known mutations in SMC4 and SMC2-like subunits [2].
• A role for Drosophila SMC4 in the resolution of sister chromatids in mitosis [3].

Biological context of SMC4

• Both SMC2 and SMC4 are essential for chromosome transmission in anaphase [4].
• Mitotic transmission of chromosome III carrying the rDNA translocation is impaired in smc2 and smc4 mutants [4].
• In vivo localization of Smc4p fused to green fluorescent protein showed that, unexpectedly, in S. cerevisiae the condensin complex concentrates in the rDNA region at the G2/M phase of the cell cycle. rDNA segregation in mitosis is delayed and/or stalled in smc2 and smc4 mutants, compared with separation of pericentromeric and distal arm regions [4].

Other interactions of SMC4

• A disruption allele of SMT4 has a prominent chromosome phenotype: impaired targeting of Smc4p-GFP to rDNA chromatin [5].

References