Project description:Severe congenital neutropenia (CN) is a pre-leukemia syndrome that, in the majority of patients, is caused by heterogeneous ELANE mutations encoding neutrophil elastase (NE). To study leukemogenesis associated with CN we generated CN and CN/AML patient-specific induced pluripotent stem cells (iPSCs). Additional mutations in leukemia-relevant genes, CSF3R and RUNX1, were introduced using CRISPR/Cas9 gene-editing. Consequently, we performed in vitro embryoid body (EB)-based hematopoietic and myeloid differentiation of generated iPSC lines. On day 14-17 of EB-based differentiation, iPSC-derived CD45+CD34+ cells were harvested and mRNA was isolated using RNeasy Mini- or Micro Kit (Qiagen). Sequencing libraries were prepared using the TruSeq RNA Sample Prep Kit (Illumina). Poly (A) selected single-read and pair-read sequencing libraries were sequenced on the Illumina platform in order to compare the transcriptomes of CN and CN/AML iPSCs-derived HSPCs from 2 CN/AML patients. Next, we identified that BAALC knockout resulted in a dramatic induction of granulocytic differentiation and a significant reduction in proliferation of CN/AML iPSC-derived HSPCs. To identify BAALC-dependent leukemia-associated gene expression, we compared the transcriptomes of CN/AML iPSCs before and after BAALC KO using a similar approach described above for CN and CN/AML iPSCs-derived HSPCs.
Project description:Endosymbiotic bacteria associated with eukaryotic hosts are omnipresent in nature, particularly in insects. Studying the bacterial side of host-symbiont interactions is, however, often limited by the unculturability and genetic intractability of the symbionts. Spiroplasma poulsonii is a maternally transmitted bacterial endosymbiont that is naturally associated with several Drosophila species. S. poulsonii strongly affects its host’s physiology, for example by causing male killing or by protecting it against various parasites. Despite intense work on this model since the 1950s, attempts to cultivate endosymbiotic Spiroplasma in vitro have failed so far. Here, we developed a method to sustain the in vitro culture of S. poulsonii by optimizing a commercially accessible medium. We also provide a complete genome assembly, including the first sequence of a natural plasmid of an endosymbiotic Spiroplasma species. Last, by comparing the transcriptome of the in vitro culture to the transcriptome of bacteria extracted from the host, we identified genes putatively involved in host-symbiont interactions. This work provides new opportunities to study the physiology of endosymbiotic Spiroplasma and paves the way to dissect insect-endosymbiont interactions with two genetically tractable partners.
