De-regulation of JNK and JAK/STAT signaling in ESCRT-II mutant tissues cooperatively contributes to neoplastic tumorigenesis

Multiple genes involved in endocytosis and endosomal protein trafficking in Drosophila have been shown to function as neoplastic tumor suppressor genes (nTSGs), including Endosomal Sorting Complex Required for Transport-II (ESCRT-II) components vacuolar protein sorting 22 (vps22), vps25, and vps36. However, most studies of endocytic nTSGs have been done in mosaic tissues containing both mutant and non-mutant populations of cells, and interactions among mutant and non-mutant cells greatly influence the final phenotype. Thus, the true autonomous phenotype of tissues mutant for endocytic nTSGs remains unclear. Here, we show that tissues predominantly mutant for ESCRT-II components display characteristics of neoplastic transformation and then undergo apoptosis. These neoplastic tissues show upregulation of c-Jun N-terminal Kinase (JNK), Notch, and Janus Kinase (JAK)/Signal Transducer and Activator of Transcription (STAT) signaling. Significantly, while inhibition of JNK signaling in mutant tissues partially inhibits proliferation, inhibition of JAK/STAT signaling rescues other aspects of the neoplastic phenotype. This is the first rigorous study of tissues predominantly mutant for endocytic nTSGs and provides clear evidence for cooperation among de-regulated signaling pathways leading to tumorigenesis

Notch Signaling Activates Yorkie Non-Cell Autonomously in Drosophila

In Drosophila imaginal epithelia, cells mutant for the endocytic neoplastic tumor suppressor gene vps25 stimulate nearby untransformed cells to express Drosophila Inhibitor-of-Apoptosis-Protein-1 (DIAP-1), conferring resistance to apoptosis non-cell autonomously. Here, we show that the non-cell autonomous induction of DIAP-1 is mediated by Yorkie, the conserved downstream effector of Hippo signaling. The non-cell autonomous induction of Yorkie is due to Notch signaling from vps25 mutant cells. Moreover, activated Notch in normal cells is sufficient to induce non-cell autonomous Yorkie activity in wing imaginal discs. Our data identify a novel mechanism by which Notch promotes cell survival non-cell autonomously and by which neoplastic tumor cells generate a supportive microenvironment for tumor growth

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Excess free histone H3 localizes to centrosomes for proteasome-mediated degradation during mitosis in metazoans

The cell tightly controls histone protein levels in order to achieve proper packaging of the genome into chromatin, while avoiding the deleterious consequences of excess free histones. Our accompanying study has shown that a histone modification that loosens the intrinsic structure of the nucleosome, phosphorylation of histone H3 on threonine 118 (H3 T118ph), exists on centromeres and chromosome arms during mitosis. Here, we show that H3 T118ph localizes to centrosomes in humans, flies, and worms during all stages of mitosis. H3 abundance at the centrosome increased upon proteasome inhibition, suggesting that excess free histone H3 localizes to centrosomes for degradation during mitosis. In agreement, we find ubiquitinated H3 specifically during mitosis and within purified centrosomes. These results suggest that targeting of histone H3 to the centrosome for proteasome-mediated degradation is a novel pathway for controlling histone supply, specifically during mitosis

Tissues predominantly mutant for ESCRT-II components <i>vps22</i>, <i>vps25</i>, or <i>vps36</i> show neoplastic characteristics.

<p>Shown are predominantly mutant eye-antennal imaginal discs. Phalloidin (green) is used to mark the overall shape of the tissue. Scale bars represent 50 µm. (<b>A–D</b>) BrdU (red and grayscale) labelings show that proliferation is increased in discs predominantly mutant for <i>vps22</i> (B,B’), <i>vps25</i> (C,C’), or <i>vps36</i> (D,D’), as compared to proliferation in control discs (A,A’). (<b>E–H</b>) aPKC (red and grayscale (E’,F’,G’,H’)) and Dlg (green and grayscale (E’’’,F’’’,G’’’,H’’’)) labelings of discs predominantly mutant for <i>vps22</i> (F–F’’’), <i>vps25</i> (G–G’’’), or <i>vps36</i> (H–H’’’) show that cellular architecture is disrupted, as compared to the architecture of control discs (E–E’’’). (<b>I–L</b>) ELAV (red and grayscale) labelings of discs predominantly mutant for <i>vps22</i> (J,J’), <i>vps25</i> (K,K’), or <i>vps36</i> (L,L’) show that very few cells in the mutant discs differentiate normally, as compared to differentiation in control discs (I,I’). (<b>M–P</b>) Mmp1 (red and grayscale) labelings of discs predominantly mutant for <i>vps22</i> (N,N’), <i>vps25</i> (O,O’), or <i>vps36</i> (P,P’) show that levels of this protein are elevated, as compared to Mmp1 levels in control discs (M,M’). <b>Genotypes</b>: (<b>A</b>) <i>eyFLP;; FRT82B/FRT82B cl</i>. (<b>E,I,M</b>) <i>eyFLP; FRT42D y⁺/FRT42D cl</i>. (<b>B,F,J,N</b>) <i>eyFLP;; FRT82B vps22^5F3-8/FRT82B cl</i>. (<b>C,G,K,O</b>) <i>eyFLP; FRT42D vps25^N55 y⁺/FRT42D cl</i>. (<b>D,H,L,P</b>) <i>eyFLP;; vps36^Δ69 FRT80B/cl FRT80B</i>.</p

Inhibition of JAK/STAT signaling partially rescues the neoplastic transformation of ESCRT-II mutant tissue.

<p>Shown are predominantly mutant eye-antennal imaginal discs. Phalloidin (green) is used to mark the overall shape of the tissue. Scale bars represent 50 µm. (<b>A,B</b>) BrdU (red and grayscale) labelings show that proliferation is elevated in tissues predominantly mutant for <i>vps22</i> and <i>Stat92E</i> (B,B’) Proliferation is slightly abnormal in control tissues predominantly mutant for <i>Stat92E</i> (A,A’). (<b>C,D</b>) aPKC (red and grayscale (C’,D’)) and Dlg (green and grayscale (C’’’,D’’’)) labelings of discs predominantly mutant for <i>vps22</i> and <i>Stat92E</i> show that cellular architecture is largely intact (D–D’’’). Cellular architecture is not disrupted in control discs predominantly mutant for <i>Stat92E</i> (C–C’’’). (<b>E,F</b>) ELAV (red and grayscale) labelings of discs predominantly mutant for <i>vps22</i> and <i>Stat92E</i> show that differentiation is completely rescued (F,F’) from the loss of differentiation seen in ESCRT-II mutant discs. Differentiation occurs normally in control discs predominantly mutant for <i>Stat92E</i> (E,E’). (<b>G,H</b>) Mmp1 (red and grayscale) labelings of discs predominantly mutant for <i>vps22</i> and <i>Stat92E</i> show that levels of this protein are increased (H,H’). Mmp1 levels are not affected in control discs predominantly mutant for <i>Stat92E</i> (G,G’). <b>Genotypes</b>: (<b>A,C,E,G</b>) <i>eyFLP;; FRT82B Stat92E³⁹⁷/FRT82B cl.</i> (<b>B,D,F,H</b>) <i>eyFLP;; FRT82B vps22^5F3-8 Stat92E³⁹⁷/FRT82B cl</i>.</p

Animals with imaginal discs predominantly mutant for ESCRT-II components die as headless pharate pupae.

<p>Animals with predominantly mutant tissues are generated with the <i>eyFLP-cl</i> system. (<b>A,B</b>) Animals with eye-antennal imaginal discs predominantly mutant for <i>vps22</i> (A) or <i>vps25</i> (B) die as pharate pupae that lack heads. <b>Genotypes</b>: (<b>A</b>) <i>eyFLP;; FRT82B vps22^5F3-8/FRT82B cl.</i> (<b>B</b>) <i>eyFLP; FRT42D vps25^N55 y⁺/FRT42D cl</i>.</p

Imaginal discs predominantly mutant for <i>vps22</i>, <i>vps25</i>, or <i>vps36</i> are apoptotic.

<p>Shown are predominantly mutant eye-antennal imaginal discs. Phalloidin (green) or DAPI (green) is used to mark the overall shape of the tissue. Scale bars represent 50 µm. (<b>A–D</b>) Cleaved Caspase-3 (Cas-3*; red and grayscale) labelings show that apoptosis is increased in discs predominantly mutant for <i>vps22</i> (B), <i>vps25</i> (C), or <i>vps36</i> (D), as compared to apoptosis in control discs (A,A’). (<b>E–H</b>) TUNEL (red and grayscale) labelings show that apoptosis is increased in discs predominantly mutant for <i>vps22</i> (F), <i>vps25</i> (G), or <i>vps36</i> (H), as compared to apoptosis in control discs (E,E’). <b>Genotypes</b>: (<b>A</b>) <i>eyFLP; FRT42D y⁺/FRT42D cl.</i> (<b>B,F</b>) <i>eyFLP;; FRT82B vps22^5F3-8/FRT82B cl.</i> (<b>C,G</b>) <i>eyFLP; FRT42D vps25^N55/FRT42D cl.</i> (<b>D,H</b>) <i>eyFLP;; vps36^Δ69 FRT80B/cl FRT80B.</i> (<b>E</b>) <i>eyFLP;; FRT82B/FRT82B cl.</i></p

Notch, JAK/STAT, and JNK signaling are upregulated in <i>vps22</i>, <i>vps25</i>, and <i>vps36</i> mutant tissues.

<p>Shown are predominantly mutant eye-antennal imaginal discs. Phalloidin (green) is used to mark the overall shape of the tissue. <i>Gbe-Su(H)-lacZ</i>, and <i>E(spl)m8 2.61-lacZ</i> are detected by β-gal labeling (red or grayscale). Scale bars represent 50 µm. (<b>A,E</b>) Imaginal discs predominantly mutant for <i>vps25</i> induce high levels of <i>Gbe-Su(H)-lacZ</i> (E), as compared to control discs (A,A’). (<b>B,C,E</b>) Imaginal discs predominantly mutant for <i>vps22</i> (C) or <i>vps36</i> (E) induce high levels of <i>E(spl)m8 2.61-lacZ</i>, as compared to control discs (B,B’). (F–I) Imaginal discs predominantly mutant for <i>vps22</i> (G), <i>vps25</i> (H), or <i>vps36</i> (I) induce high levels of <i>10X-STAT-GFP</i>, as compared to control discs (F,F’). (J–M) Imaginal discs predominantly mutant for <i>vps22</i> (K), <i>vps25</i> (L), or <i>vps36</i> (M) show high levels of phosphorylated JNK protein, as compared to control discs (J,J’). <b>Genotypes</b>: (<b>A</b>) <i>eyFLP; FRT42D y⁺/FRT42D cl; Gbe-Su(H)-lacZ/+.</i> (<b>B</b>) <i>eyFLP; E(Spl)m8 2.61-lacZ/+; FRT82B/FRT82B cl.</i> (<b>C</b>) <i>eyFLP; E(spl)m8 2.61-lacZ/+; FRT82B vps22^5F3-8/FRT82B cl.</i> (<b>D</b>) <i>eyFLP; FRT42D vps25^N55 y⁺/FRT42D cl; Gbe-Su(H)-lacZ/+.</i> (<b>E</b>) <i>eyFLP; E(spl)m8 2.61-lacZ/+; vps36^Δ69 FRT80B/cl FRT80B.</i> (<b>F</b>) <i>eyFLP; FRT42D y⁺/FRT42D cl; 10X-STAT-GFP/+.</i> (<b>G</b>) <i>eyFLP; 10X-STAT-GFP/+; FRT82B vps22^5F3-8/FRT82B cl.</i> (<b>H</b>) <i>eyFLP; FRT42D vps25^N55 y⁺/FRT42D cl; 10X-STAT-GFP/+.</i> (<b>I</b>) <i>eyFLP; 10X-STAT-GFP/+; vps36^Δ69 FRT80B/cl FRT80B.</i> (<b>J</b>) <i>eyFLP; FRT42D y⁺/FRT42D cl.</i> (<b>K</b>) <i>eyFLP;; FRT82B vps22^5F3-8/FRT82B cl.</i> (<b>L</b>) <i>eyFLP; FRT42D vps25^N55 y⁺/FRT42D cl.</i> (<b>M</b>) <i>eyFLP;; vps36^Δ69 FRT80B/cl FRT80B.</i></p