S. cerevisiae Srs2 helicase ensures normal recombination intermediate metabolism during meiosis and prevents accumulation of Rad51 aggregates.

We investigated the meiotic role of Srs2, a multi-functional DNA helicase/translocase that destabilises Rad51-DNA filaments and is thought to regulate strand invasion and prevent hyper-recombination during the mitotic cell cycle. We find that Srs2 activity is required for normal meiotic progression and spore viability. A significant fraction of srs2 mutant cells progress through both meiotic divisions without separating the bulk of their chromatin, although in such cells sister centromeres often separate. Undivided nuclei contain aggregates of Rad51 colocalised with the ssDNA-binding protein RPA, suggesting the presence of persistent single-strand DNA. Rad51 aggregate formation requires Spo11-induced DSBs, Rad51 strand-invasion activity and progression past the pachytene stage of meiosis, but not the DSB end-resection or the bias towards interhomologue strand invasion characteristic of normal meiosis. srs2 mutants also display altered meiotic recombination intermediate metabolism, revealed by defects in the formation of stable joint molecules. We suggest that Srs2, by limiting Rad51 accumulation on DNA, prevents the formation of aberrant recombination intermediates that otherwise would persist and interfere with normal chromosome segregation and nuclear division.

Posttraumatic stress symptoms and well-being following relationship dissolution: past trauma, alexithymia, suppression.

To investigate whether posttraumatic stress disorder (PTSD) from past trauma, alexithymia and suppression would impact on the experience of Posttraumatic Stress symptoms (PTSS) and psychological well-being following romantic relationship dissolution. One hundred and eighty-nine participants completed questionnaires measuring PTSD, alexithymia, suppression, PTSS and psychological well-being. The results showed that following relationship dissolution, higher levels of intrusion and avoidance (PTSS) and lower levels of psychological well-being were associated with PTSD from past trauma. Difficulty describing feelings was associated negatively with intrusion; difficulty identifying feelings was associated positively with psychological well-being. Suppression was associated negatively with avoidance. To conclude, PTSD from past traumas was related to PTSS symptoms and poor psychological well-being. Alexithymia and suppression were also related to the above outcomes but in a symptom-specific manner.