Schlegelberger, B. | bioRxiv Science

bioRxiv2023

Altered enhancer-promoter interaction leads to MNX1 expression in pediatric acute myeloid leukemia with t(7;12)(q36;p13)

Acute myeloid leukemia (AML) with the t(7;12)(q36;p13) translocation occurs only in very young children and has a poor clinical outcome. The expected oncofusion between breakpoint partners (MNX1 and ETV6) has only been reported in a subset of cases. However, a universal feature is the strong transcript and protein expression of MNX1, a homeobox transcription factor that is normally not expressed in hematopoietic cells. Here, we map the translocation breakpoints on chromosomes 7 and 12 in affected patients to a region proximal to MNX1 and either introns 1 or 2 of ETV6. The frequency of MNX1 overexpression in pediatric AML (n=1556, own and published data) is 2.4% and occurs predominantly in t(7;12)(q36;p13) AML. Chromatin interaction assays in a t(7;12)(q36;p13) iPSC cell line model unravel an enhancer-hijacking event that explains MNX1 overexpression in hematopoietic cells. Our data suggest that enhancer-hijacking is a more common and overlooked mechanism for structural rearrangement-mediated gene activation in AML. Key pointsO_LIExpression analysis of over 1500 pediatric AML samples demonstrates MNX1 expression as a universal feature of t(7;12)(q36;p13) AML as well as in rare cases without t(7;12)(q36;p13) C_LIO_LIMNX1 is activated by an enhancer-hijacking event in t(7;12)(q36;p13) AML and not, as previously postulated, by the creation of a MNX1::ETV6 oncofusion gene. C_LI

cancer biology↗

bioRxiv2019

The knockout of the HMG-Domain of the porcine SRY-gene by CRISPR/Cas RNP microinjection causes sex reversal in gene-edited pigs

1The sex-determining region on the Y chromosome (SRY) is thought to be the central genetic element of male sex development. Mutations within the SRY gene are associated with a male-to-female sex reversal syndrome in humans and other mammalian species such as mice and rabbits. However, the underlying mechanisms are largely unknown. To understand the biological function of the SRY gene, a site-directed mutational analysis is required to investigate associated phenotypic changes at the molecular, cellular and morphological level. In our study, we successfully generated a knockout of the porcine SRY gene by microinjection of two clustered regularly interspaced short palindromic repeats (CRISPR) - associated protein - 9 nuclease (Cas9) ribonucleoprotein (RNP) complexes targeting the centrally located "high mobility group" (HMG) domain of the SRY gene. Mutations within this region resulted in the development of complete external and internal female genitalia in genetically male pigs. The internal female genitalia including uteri, ovaries, and oviducts, revealed substantial size differences in 9-months old SRY-knockout pigs compared to age-matched female wild type controls. In contrast, a deletion within the 5 flanking region of the HMG domain was not associated with sex reversal. Results of this study demonstrates for the first time the central role of the HMG domain of the SRY gene in male sex determination in pigs. Moreover, quantitative analysis by digital PCR revealed evidence for a duplication of the porcine SRY locus. Our results pave the way towards the generation of boars exclusively producing phenotypically female offspring to avoid surgical castration without anesthesia in piglets. Moreover, the study establishes a large animal model that is much more similar to humans in regard of physiology and anatomy and pivotal for longitudinal studies.

developmental biology↗