Role for the fission yeast RecQ helicase in DNA repair in G2.

Members of the RecQ helicase subfamily are mutated in several human genomic instability syndromes, such as Bloom, Werner, and Rothmund-Thomson syndromes. We show that Rqh1, the single Schizosaccharomyces pombe homologue, is a 3'-to-5' helicase and exists with Top3 in a high-molecular-weight complex. top3 deletion is inviable, and this is suppressed by concomitant loss of rqh1 helicase activity or loss of recombination functions. This is consistent with RecQ helicases in other systems. By using epistasis analysis of the UV radiation sensitivity and by analyzing the kinetics of Rhp51 (Rad51 homologue), Rqh1, and Top3 focus formation in response to UV in synchronized cells, we identify the first evidence of a function for Rqh1 and Top3 in the repair of UV-induced DNA damage in G(2). Our data provide evidence that Rqh1 functions after Rad51 focus formation during DNA repair. We also identify a function for Rqh1 upstream of recombination in an Rhp18-dependent (Rad18 homologue) pathway. The model that these data allow us to propose helps to reconcile different interpretations of RecQ family helicase function that have arisen between work based on the S. pombe system and models based on studies of Saccharomyces cerevisiae SGS1 suggesting that RecQ helicases act before Rad51

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Masteroppgave i helseledelse(EMBA) - Nord universitet 202

Biochemical Changes During the First Year of Feminizing Hormone Therapy in Transfeminine Individuals

BACKGROUND: Persons with assigned male sex at birth (AMAB) might wish to obtain feminization and/or demasculinization according to the person's gender identity and are therefore treated with estradiol and/or antiandrogens. AIM: The aim was to evaluate biochemical changes and side effects in AMAB individuals treated with guideline-based feminizing hormone treatment (FHT). METHODS: Medical charts of 99 AMAB individuals ≥ 18 years referred to the Center for Gender Identity; Aalborg University hospital, Denmark, between January 2017 and July 2019 were reviewed to identify adverse side effects. Furthermore, data from the laboratory information system (Labka II) were retrieved to obtain biochemical parameters. Biochemical plasma concentrations after initiation of FHT were compared to concentrations prior to FHT and to existing guidelines. OUTCOMES: After 11–19 months, 29% of the trans feminine individuals had plasma estradiol concentrations within the treatment target. RESULTS: The plasma concentration of estradiol varies greatly during FHT. Plasma levels of estrogen were within the treatment target after 11–19 months of treatment, whereas 100% had concentrations within the reference range for premenopausal cis-women. Furthermore, plasma concentrations of lipids and hematological parameters approached female reference ranges after 11 months of FHT. CLINICAL IMPLICATIONS: The target levels of plasma estradiol concentrations during FHT could be expanded, making the wanted physiological changes easier to obtain. STRENGTHS & LIMITATION: This cohort study included 99 AMAB individuals and biochemical evaluation was possible in 67 individuals. Only one individual was lost during follow-up. However, the follow-up period was limited making evaluation of long-term side effects impossible. CONCLUSION: Plasma concentration of estradiol varies greatly during guideline based FHT, making plasma estradiol levels within the target level difficult to attain. JA Hojbjerg, AD Højgaard, A-M Hvas. Biochemical Changes During the First Year of Feminizing Hormone Therapy in Transfeminine Individuals. Sex Med 2021;10:100472

Optimisation of the Schizosaccharomyces pombe urg1 expression system

The ability to study protein function in vivo often relies on systems that regulate the presence and absence of the protein of interest. Two limitations for previously described transcriptional control systems that are used to regulate protein expression in fission yeast are: the time taken for inducing conditions to initiate transcription and the ability to achieve very low basal transcription in the "OFF-state". In previous work, we described a Cre recombination-mediated system that allows the rapid and efficient regulation of any gene of interest by the urg1 promoter, which has a dynamic range of approximately 75-fold and which is induced within 30-60 minutes of uracil addition. In this report we describe easy-to-use and versatile modules that can be exploited to significantly tune down P urg1 "OFF-levels" while maintaining an equivalent dynamic range. We also provide plasmids and tools for combining P urg1 transcriptional control with the auxin degron tag to help maintain a null-like phenotype. We demonstrate the utility of this system by improved regulation of HO-dependent site-specific DSB formation, by the regulation Rtf1-dependent replication fork arrest and by controlling Rhp18(Rad18)-dependent post replication repair

CEP128 Localizes to the Subdistal Appendages of the Mother Centriole and Regulates TGF-β/BMP Signaling at the Primary Cilium

Summary: The centrosome is the main microtubule-organizing center in animal cells and comprises a mother and daughter centriole surrounded by pericentriolar material. During formation of primary cilia, the mother centriole transforms into a basal body that templates the ciliary axoneme. Ciliogenesis depends on mother centriole-specific distal appendages, whereas the role of subdistal appendages in ciliary function is unclear. Here, we identify CEP128 as a centriole subdistal appendage protein required for regulating ciliary signaling. Loss of CEP128 did not grossly affect centrosomal or ciliary structure but caused impaired transforming growth factor-β/bone morphogenetic protein (TGF-β/BMP) signaling in zebrafish and at the primary cilium in cultured mammalian cells. This phenotype is likely the result of defective vesicle trafficking at the cilium as ciliary localization of RAB11 was impaired upon loss of CEP128, and quantitative phosphoproteomics revealed that CEP128 loss affects TGF-β1-induced phosphorylation of multiple proteins that regulate cilium-associated vesicle trafficking. : Mönnich et al. show that CEP128 localizes to the subdistal appendages of the mother centriole and basal body of the primary cilium. CEP128 regulates vesicular trafficking and targeting of RAB11 to the primary cilium. CEP128 loss leads to impaired TGF-β/BMP signaling, which, in zebrafish, is associated with defective organ development. Keywords: primary cilium, basal body, centriole, subdistal appendage, centrosome, transforming growth factor β, TGF-β, bone morphogenetic protein, BMP, zebrafish, phosphoproteomics, CEP12