Transcription factor Sp1 regulates mitotic chromosome assembly and segregation.

Aneuploidy is a pervasive feature of cancer cells that results from chromosome missegregation. Several transcription factors have been associated with aneuploidy; however, no studies to date have demonstrated that mammalian transcription factors directly regulate chromosome segregation during mitosis. Here, we demonstrate that the ubiquitously expressed transcription factor specificity protein 1 (Sp1), which we have previously linked to aneuploidy, has a mitosis-specific role regulating chromosome segregation. We find that Sp1 localizes to mitotic centromeres and auxin-induced rapid Sp1 degradation at mitotic onset results in chromosome segregation errors and aberrant mitotic progression. Furthermore, rapid Sp1 degradation results in anomalous mitotic chromosome assembly characterized by loss of condensin complex I localization to mitotic chromosomes and chromosome condensation defects. Consistent with these defects, Sp1 degradation results in reduced chromosome passenger complex activity and histone H3 serine 10 phosphorylation during mitosis, which is essential for condensin complex I recruitment and chromosome condensation. Together, these data provide the first evidence of a mammalian transcription factor acting specifically during mitosis to regulate chromosome segregation.

Nanoparticle Concentration in Surgical Plume During Tonsillectomy: A Comparison of Four Techniques.

OBJECTIVE: Surgical plume has known potential occupational health hazards. This study compares nanoparticle concentrations in surgical plumes generated between different pediatric tonsillectomy surgical techniques and assesses the efficacy of mitigation measures. METHODS: This is a cross-sectional study performed at a tertiary care academic center. Extracapsular or intracapsular tonsillectomy was performed in 60 patients using four techniques and in 10 additional patients using mitigation measures. Two nanoparticle counters were used to measure particulate concentrations: CPC™ and DiSCmini™. Tonsillectomy techniques included: (1) microdebrider (MD), (2) Bovie with manual suctioning by an assistant (B), (3) Bovie with built-in smoke evacuation system (BS), and (4) Coblator™ (CB). An additional Yankauer suction was used in the mitigation groups (BSY) and (CBY). Comparative analysis was performed using one-way ANOVA on ranks and pairwise comparisons between the groups. RESULTS: The mean concentrations (particles/cm3) and coefficient of variants for the DiSCmini particulate counter were MD: 5140 (1.6), B: 30700 (1.5), BS: 25001 (0.8), CB: 54814 (1.7), CBY: 2395 (1.3) and BSY: 11552 (1.0). Mean concentrations for the CPC particulate counter were MD: 1223 (1.4), B: 3405 (0.7), BS: 5002 (0.9), CB: 13273 (1.0), CBY: 1048 (1.2) and BSY: 3046 (0.6). The lowest mean concentrations were noted in cases using MD and the highest in cases using CB. However, after mitigation, CBY had the lowest overall levels. CONCLUSION: Tonsillectomy technique does impact the levels of nanoparticles emitted within the surgical plume, which may present an occupational hazard for operating room personnel. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:2444-2448, 2024.