TABLE 2.
Tissue specific DOT1L-KO studies during development or differentiation.
| Tissue | KO strategy | H3K79me | Phenotype |
|---|---|---|---|
| Maternal oocyte | Zp3-Cre, Dot1l Exon2 LoxP | H3K79me1/2 IF of oocytes | No affect on development or fertility of F1 pups. No affect on establishment imprinting in oocyte or maintenance in embryo. Liao and Szabó. (2020) |
| Cartilage | Col2a1-Cre, Dot1l Exon2 LoxP | Severely reduced Mendelian ratio of live births (8/58 expected). Only one survived to adulthood but with growth retardation. P2 pups had accelerated ossification and advanced mineralization. Aberrant Col10a1 expression in epiphyseal chondrocytes. Jo et al. (2020) | |
| Limb mesenchyme progenitor | Prrx1-Cre, Dot1l Exon5 LoxP | H3K79me2 IB of chondrocytes | Long bone shortening at birth, structural forelimb abnormalities in neonates, forelimb dislocations, fibula thickening, disorganized growth plate at 3 weeks, poor locomotion, reduced extracellular matrix production. Sutter et al. (2021) |
| Chondrocyte | Col2-cre, Dot1l Exon2 LoxP | Severe growth retardation, disorganized prehypertropic zone of growth plates, and increased WNT pathway activation. Monteagudo et al. (2017) | |
| Intestinal epithelium | Villin-CreER, Dot1L Exon5 LoxP | H3K79me2 IHC of intestinal crypts | Induced deletion with tamoxifen at 4 weeks. 3 weeks to 4 months post deletion: No weight loss or malnourishment. Normal intentional morphology. Increased crypt apoptosis. Very few transcriptional alterations. Ho et al. (2013) |
| Granule cell precursor (cerebellum) | Atoh1-Cre Dot1l Exon2 LoxP | H3K79me1/2/3 IF of cerebellum | Small cerebellum with motor deficiencies at 9 weeks. At P3: Thin external granular layer and disorganized internal granular layer of cerebellum. Fewer dividing and differentiating progenitor cells. Bovio et al. (2019) |
| Mature Purkinje cell | Pcp2-Cre Dot1l Exon2 LoxP | H3K79me1/2/3 IF of cerebellum | No obvious phenotype. Bovio et al. (2019) |
| Cerebral cortex | Foxg1-Cre, Emx1-Cre, Dot1l LoxP | Lethality minutes after birth, microcephaly of ventral and dorsal structures at P0, depletion of neural progenitor cells through premature differentiation into deep layer neurons at E12.5–E14.5. Franz et al. (2019) | |
| Cardiac | Mhc-Cre, Dot1l Exon 5–6 LoxP | H3K79me2/3 IF and IB of heart extract | Premature death (50% within 2 weeks post-birth). At P10: enlarged hearts, increased apoptosis, aberrant fetal cardiac gene expression. A maintenance of proliferating cells at P1 and P5. Downregulation of dystrophin and its exogenous expression post-birth rescued some of the KO phenotypes. Nguyen et al. (2011) |
| Endothelial cells | Tie2-Cre, Dot1l Exon 5–6 LoxP | Normal development at E12.5. E13.5: edema, hemorrhage spots, and lethality. The pups that were born died by 3 weeks and had chylous ascites. Yoo et al. (2020) | |
| Lymphatic endothelial cells | Lyve1-Cre, Dot1l Exon 5–6 LoxP | No observable phenotype. Yoo et al. (2020) | |
| Definitive hematopoietic stem cells | Vav-Cre, Dot1l Exon5 LoxP | H3K79me2 IB of peripheral blood nucleated cells | Varying degrees of anemia at 3–6 weeks. Decreased bone marrow cellularity. Reduced red blood cells and a smaller reduction of white blood cells. Bernt et al. (2011) |
| T cells | Lck-Cre, Dot1l Exon2 LoxP | H3K79me2 IHC and flow cytometry of thymus | Differentiation of naïve CD8+ to memory T cells in the absence of immunological challenge. De-repression of developmental genes and poor immune response. Kwesi-Maliepaard et al. (2020) |
| T cells | Cd4-Cre, Dot1l Exon2 LoxP | H3K79me2 IB of T cell subsets | Reduction in CD4+ T cells by cell death. Increased T cell receptor signaling with overproduction of IFN-γ, Reduced Th2/increased Th1 immune response. Scheer et al. (2020) |
| B cells | Mb1-Cre, Dot1l Exon2 LoxP | I. H3K79me2 flow cytometry in bone marrow and splenic B cells | I. 1.6-fold reduction in bone marrow B lineage cells by inhibiting pro-B to pre-B cell maturation at 6–8 weeks old. Inability to form germinal centers. Premature acquisition of plasma cell characteristics. Aslam et al. (2021) II. Reduction of peripheral mature B cells. Kealy et al. (2020) |
| Mature B cells | Cd23-Cre, Dot1l Exon2 LoxP | H3K79me2 IB of B cell subsets | Lack of germinal centers and memory B cells; reduced class-switched plasma cells upon challenge. Similar proliferation of B cells. Kealy et al. (2020) |
| Kidney connecting tubule/collecting duct | Aqp2-Cre, Dot1l Exon5 LoxP | Normal at 5 months, kidney fibrosis at 14 months. Wu et al. (2013); Zhang et al. (2020) |
IF, immunofluorescence; IB, immunoblot; IHC, immunohistochemistry.