Small-eared shrews of the New World genus Cryptotis (Eulipotyphla, Soricidae) comprise at least 42 species that traditionally have been partitioned among four or more species groups based on morphological characters. The Cryptotis mexicana species group is of particular interest, because its member species inhibit a subtly graded series of forelimb adaptations that appear to correspond to locomotory behaviors that range from more ambulatory to more fossorial. Unfortunately, the evolutionary relationships both among species in the C. mexicana group and among the species groups remain unclear. To better understand the phylogeny of this group of shrews, we sequenced two mitochondrial and two nuclear genes. To help interpret the pattern and direction of morphological changes, we also generated a matrix of morphological characters focused on the evolutionarily plastic humerus. We found significant discordant between the resulting molecular and morphological trees, suggesting considerable convergence in the evolution of the humerus. Our results indicate that adaptations for increased burrowing ability evolved repeatedly within the genus Cryptotis.

bAcute myeloid leukemia (AML) is characterized by increased proliferation and blocked differentiation of hematopoietic progenitors mediated, in part, by altered myeloid transcription factor expression. Decreased Krüppel-like factor 4 (KLF4) expression has been observed in AML, but how decreased KLF4 contributes to AML pathogenesis is largely unknown. We demonstrate decreased KLF4 expression in AML patient samples with various cytogenetic aberrations, confirm that KLF4 overexpression promotes myeloid differentiation and inhibits cell proliferation in AML cell lines, and identify new targets of KLF4. We have demonstrated that microRNA 150 (miR-150) expression is decreased in AML and that reintroducing miR-150 expression induces myeloid differentiation and inhibits proliferation of AML cells. We show that KLF family DNA binding sites are necessary for miR-150 promoter activity and that KLF2 or KLF4 overexpression induces miR-150 expression. miR-150 silencing, alone or in combination with silencing of CDKN1A, a well-described KLF4 target, did not fully reverse KLF4-mediated effects. Gene expression profiling and validation identified putative KLF4-regulated genes, including decreased MYC and downstream MYC-regulated gene expression in KLF4-overexpressing cells. Our findings indicate that decreased KLF4 expression mediates antileukemic effects through regulation of gene and microRNA networks, containing miR-150, CDKN1A, and MYC, and provide mechanistic support for therapeutic strategies increasing KLF4 expression.A cute myeloid leukemia (AML) is characterized by increased self-renewal of leukemia stem or progenitor cells and a failure of differentiation to mature myeloid cells. Normal hematopoietic cell differentiation and proliferation are regulated by the expression and interaction of specific transcription factors (1, 2), which are altered in AML (3-5). Elucidation of the genomic landscape of AML has further highlighted that alterations in myeloid transcription factors play a significant role in leukemogenesis (4). Recent attention has focused on the role of aberrant expression of the Krüppel-like factor (KLF) family of transcription factors in cancer (5). This family includes 17 different isoforms that bind to GCrich regions of DNA via three zinc finger domains and regulate the transcriptional activity of target genes by using two glutaminerich transactivation domains (5). KLF4 regulates differentiation of epidermal and vascular smooth muscle cells (6, 7), as well as cellular reprogramming to induce pluripotent stem cells (8). In normal hematopoiesis, KLF2 and KLF4 regulate myeloid differentiation and KLF4 expression induces CDKN1A (p21), which contributes to cell cycle arrest (9-13). In T-cell acute lymphoblastic leukemia (T-ALL) (14) and B-cell lymphomas, KLF4 has been described as a tumor suppressor regulating proliferation, apoptosis, and differentiation (15). A recent study showed that the homeobox transcription factor CDX2 represses KLF4 in myeloid leukemia cells (16). The investigators also observed that C...

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