Identification of a hTid-1 mutation which sensitizes gliomas to apoptosis

Human Tid-1 (hTid-1) is a DnaJ chaperone protein with homology to the Drosophila tumor suppressor Tid56. We report the first case of a tumor-associated mutation at the human TID1 locus, which was identified in the SF767 glioma cell line giving rise to aberrantly high levels of a hTid-1(L) mutant variant. In this study, we set out to determine whether this change in hTid-1 status influences the response of glioma cells to adenoviral (Ad)-mediated delivery of the two major isoforms of TID1, hTid-1(L) and hTid-1(S). Ad-hTid-1(S) induced apoptosis in hTid-1 mutant SF767 cells, while causing growth arrest in wild-type hTid-1-expressing U373 and U87 cells. By contrast, Ad-hTid-1(L) infection had no apparent effect on glioma cell growth. The apoptosis induced by hTid-1(S) was accompanied by mitochondrial cytochrome C release and caspase activation and blocked by stable overexpression of Bcl-X(L). Our findings suggest that the status of hTid-1 in gliomas may contribute to their susceptibility to cell death triggers.     

Drosophila Cand1 regulates Cullin3-dependent E3 ligases by affecting the neddylation of Cullin3 and by controlling the stability of Cullin3 and adaptor protein

Cullin-RING ubiquitin ligases (CRLs), which comprise the largest class of E3 ligases, regulate diverse cellular processes by targeting numerous proteins. Conjugation of the ubiquitin-like protein Nedd8 with Cullin activates CRLs. Cullin-associated and neddylation-dissociated 1 (Cand1) is known to negatively regulate CRL activity by sequestering unneddylated Cullin1 (Cul1) in biochemical studies. However, genetic studies of Arabidopsis have shown that Cand1 is required for optimal CRL activity. To elucidate the regulation of CRLs by Cand1, we analyzed a Cand1 mutant in Drosophila. Loss of Cand1 causes accumulation of neddylated Cullin3 (Cul3) and stabilizes the Cul3 adaptor protein HIB. In addition, the Cand1 mutation stimulates protein degradation of Cubitus interruptus (Ci), suggesting that Cul3-RING ligase activity is enhanced by the loss of Cand1. However, the loss of Cand1 fails to repress the accumulation of Ci in Nedd8^AN015 or CSN5^null mutant clones. Although Cand1 is able to bind both Cul1 and Cul3, mutation of Cand1 suppresses only the accumulation of Cul3 induced by the dAPP-BP1 mutation defective in the neddylation pathway, and this effect is attenuated by inhibition of proteasome function. Furthermore, overexpression of Cand1 stabilizes the Cul3 protein when the neddylation pathway is partially suppressed. These data indicate that Cand1 stabilizes unneddylated Cul3 by preventing proteasomal degradation. Here, we propose that binding of Cand1 to unneddylated Cul3 causes a shift in the equilibrium away from the neddylation of Cul3 that is required for the degradation of substrate by CRLs, and protects unneddylated Cul3 from proteasomal degradation. Cand1 regulates Cul3-mediated E3 ligase activity not only by acting on the neddylation of Cul3, but also by controlling the stability of the adaptor protein and unneddylated Cul3.     

A Novel Zinc Finger Protein, Zic, Is Involved in Neurogenesis, Especially in the Cell Lineage of Cerebellar Granule Cells

Abstract: To clarify the mechanism of cerebellar development, we have cloned a gene, named zic, encoding a zinc finger protein that is expressed abundantly in granule cells throughout development of the cerebellum. zic has a significant homology to the zinc finger domain of the Caenorhabditis elegans tra1 gene, the Drosophila cubitus interruptus Dominant gene, and the human GLI oncogene. An in situ hybridization study revealed that zic showed a restricted expression pattern in the granule cells and their putative precursor cells. It is also expressed at an early embryonic stage in the dorsal half of the neural tube. The expression pattern and nuclear localization were confirmed by immunohistochemical study. Furthermore, the bacterially expressed zic protein containing the zinc finger domains bound to the GLI -binding sequence. These findings suggest that zic is one of a number of nuclear factors involved in both differentiation in early development and maintenance of properties of the cerebellar granule cells.     

An Experimental Study of Competition Between the Native Sacramento Perch (Archoplites interruptus) and Introduced Bluegill (Lepomis macrochirus)

The Sacramento perch (Archoplites interruptus), a sunfish (Centrarchidae) native only to the Central Valley of California, has been eliminated from most of its native range. To examine the role of interspecific competition in this decline, a series of experiments were conducted to assess the growth, aggressive behavior, and habitat use of Sacramento perch in the presence of bluegill (Lepomis macrochirus), an introduced centrarchid. The experiments indicate that (1) Sacramento perch gain less weight and show reduced growth when placed with bluegill, but that this interaction only occurs with food limitation, and is not affected by overall fish density; (2) Sacramento perch demonstrate less aggressive behavior than bluegill, but become more aggressive when they are conspicuously larger than bluegill; (3) Sacramento perch shift their habitat use in the presence of bluegill. Overall the results imply that Sacramento perch and bluegill exhibit interspecific competition where the mechanism of interaction is aggressive dominance by bluegill. It is suggested that long term persistence of Sacramento perch may require a habitat that is free of introduced centrarchid fishes, or one controlled by a naturally variable hydrological regime.     

改良阶梯式截骨法矫正儿童创伤后肘内翻畸形

目的:探讨采用肱骨髁上改良阶梯式截骨联合钢板等内固定治疗儿童肘内翻畸形的临床疗效。方法:回顾性研究我科自2012年1月~2014年12月收治的14例肘内翻畸形患者,其中,男10例/女4例,年龄6~14岁,平均10.3岁,右侧9例/左侧5例。所有病例均有明确的伸直型肱骨髁上骨折病史,在创伤后约1.7年(1~4.5年)行改良阶梯式截骨。通过测量手术前后提携角及肘关节活动度,并依据Flynn临床肘关节功能评定标准对患肢功能进行评价。结果:本组患者术后均获得随访,随访时间12~26个月,平均17.4±2.7个月,肱骨截骨处达到骨性愈合的时间为2.5~4个月(平均2.9±0.6个月),术后畸形矫正良好,获得5.2±1.7°提携角。术后关节活动范围-0.7±1.6~134.5±2.4°,与术前相比,伸展活动的差异无统计学意义(t=0.871,P0.05);而屈曲活动改善明显,差异有统计学意义(t=18.819,P0.01)。末次随访时截骨纠正角度丢失1.4±0.8°。根据Flynn肘关节功能评定标准:优11例/良2例/可1例,优良率92.86%。均无感染、外髁突出、过度肥厚增生的术后瘢痕、血管神经损伤、关节不稳等并发症。结论:本研究针对创伤后儿童肘内翻畸形的手术疗效进行随访,发现改良阶梯式截骨的手术操作相对简单,矫形效果满意,能早期恢复肘关节功能且畸形复发率低,是一种美容效果较好的治疗肘内翻的截骨方式。     

Substance P-like immunoreactivity in the stomatogastric nervous systems of the crab Cancer borealis and the lobsters Panulirus interruptus and Homarus americanus

Summary The distribution of substance P-like immunoreactivity in the stomatogastric nervous systems of three decapod crustacean species, Cancer borealis, Homarus americanus, and Panulirus interruptus, was studied. The stomatogastric ganglion showed dense staining in the neuropil, but none in the somata. A single neuron stained in the esophageal ganglion. Lucifer yellow backfills and intracellular injections followed by incubation with the substance P antibody showed that the axons of this neuron project into the inferior esophageal nerves towards the paired commissural ganglia. The commissural ganglia showed a pronounced projection from a large bundle of fibers in the anterior medial portion of the circumesophageal connective. Additionally, less dense neuropil and stained somata were seen in the commissural ganglia. Staining was completely blocked by preabsorption with authentic substance P, physalaemin, eledoisin, and substance K. These data suggest that in the nervous system of crustacean species a molecule with C-terminal homology to substance P and other tachykinins is released as a neuroregulator in the stomatogastric ganglion.