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Saetre, F.

Publications and source records attributed to Saetre, F..

2 recordsLinked to original sources
bioRxiv2020

Separation of newly replicated bacterial chromosomes: the role of Escherichia coli Topoisomerase IV

Topoisomerase IV (TopoIV) is a vital bacterial enzyme which disentangles newly replicated DNA and enables segregation of daughter chromosomes. In bacteria, DNA replication and segregation are concurrent processes. This means that TopoIV must continually remove inter-DNA linkages during replication. There exists a short time lag of about 5-10 minutes between replication and segregation in which the daughter chromosomes are intertwined. Exactly where TopoIV binds during the cell cycle has been the subject of much debate. We show here that TopoIV localizes to the origin proximal side of the fork trailing protein SeqA and follows the movement pattern of the replication machinery in the cell.

molecular biology↗
bioRxiv2019

CD4+ T cells persist for years in the human small intestine and mediate robust Th1 immunity.

Studies in mice and humans have shown that CD8+ T cell immunosurveillance in non-lymphoid tissues is dominated by resident populations. Whether CD4+ T cells use the same strategies to survey peripheral tissues is less clear. Here, examining the turnover of CD4+ T cells in transplanted duodenum in humans, we demonstrate that the majority of CD4+ T cells were still donor-derived one year after transplantation. In contrast to memory CD4+ T cells in peripheral blood, intestinal CD4+ TRM cells expressed CD69 and CD161, but only a minor fraction expressed CD103. Functionally, intestinal CD4+ TRM cells were very potent cytokine producers; the vast majority being polyfunctional TH1 cells, whereas a minor fraction produced IL-17. Interestingly, a fraction of intestinal CD4+ T cells produced granzyme-B and perforin after activation. Together, we show that the intestinal CD4+ T-cell compartment is dominated by resident populations that survive for more than 1 year. This finding is of high relevance for the development of oral vaccines and therapies for diseases in the gut.

immunology↗