Chromosome distribution of intracisternal A-particle sequences in the Syrian hamster and mouse

Metaphase chromosomes of Syrian hamster and BALB/c mice were hybridized in situ with radiolabeled probes derived from cloned intracisternal A-particle (IAP) genes of the corresponding species. The DNAs of these species are known to contain about 900 and 1,000 copies, respectively, of the retrovirus-like IAP sequence elements per haploid genome. Multiple IAP sequences were found on all chromosomes of both hamster and mouse. In the hamster, more than half of the IAP sequences were located in regions of non-centromeric constitutive heterochromatin, at an average concentration per unit chromosome length 5 times greater than in the euchromatic regions. The other dispersed sequences showed marked local variations in concentration along the chromosome lengths; both discrete foci and large grain clusters were observed as well as regions apparently lacking IAP sequences. Within the resolution of the techniques, IAP sequences appeared to be more evenly distributed over the mouse chromosomes; however, some prominent variations in concentration were seen. The number of potentially active IAP genes in the Syrian hamster, and by extension in the mouse, may be restricted by the preferential location of IAP sequences in genetically inert regions of the genome.     

Nucleotide Sequence Relationship Between Intracisternal Type A Particles of Mus musculus and an Endogenous Retrovirus (M432) of Mus cervicolor

Intracisternal type A particles are retrovirus-like structures found in embryonic cells and many tumors of Mus musculus but having no clear relationship with other retroviruses of this mouse species. We have observed a partial nucleotide sequence homology between the high-molecular-weight (32S and 35S) RNA components of intracisternal A-particles from a neuroblastoma cell line and the 70S RNA fraction from M432, a type of retrovirus endogenous to the Asian mouse Mus cervicolor. M432 complementary DNA (cDNA) was hybridized to the extent of 30% by the A-particle RNAs. The hybrids showed a lower thermal stability (DeltaT(m), 7 degrees C) than those formed with homologous RNA. The reaction was commensurate with that found between M432 cDNA and divergent sequences in the M. musculus genome. The capacity to hybridize M432 cDNA was closely correlated with the concentration of A-particle sequences in the cytoplasmic RNA of several M. musculus cell types. The major RNA fraction of M432 virus showed a reciprocal partial reaction with the A-particle cDNA's; the virus, which was grown in NIH/3T3 (M. musculus) cells, also contained a small proportion of apparently authentic A-particle nucleotide sequences. A subset of A-particle sequences seemed to be almost totally lacking in the main M432 RNA. The A-particle cDNA's hybridized extensively with divergent sequences in M. cervicolor cellular DNA, indicating that this mouse species may contain not only the partially homologous M432 virogene, but also a more complete genetic equivalent of the intracisternal A-particle.     

Genetic relationship between the Mus cervicolor M432 retrovirus and the Mus Musculus intracisternal type A particle

The genetic relationship between the retrovirus-like intracisternal type A particle (IAP) from Mus musculus and the novel retrovirus (M432) from M. cervicolor has been determined by heteroduplex and restriction endonuclease analyses of molecular clones of the respective genomes. We have found a major homology region (3.7 kilobase pairs) which probably begins near the 3' end of the M432 gag gene, spans the pol gene, and ends in the env gene. A second region (0.6 kilobase pairs) of weak homology was also observed adjacent to the 3' long terminal repeats of the respective genomes. The IAP genome is well conserved in the cellular DNA of all species of the genus Mus. In contrast, cellular DNA sequences related to the 5' end of the M432 genome, which shares no homology with the IAP genome, are found only in M. cervicolor and the closely related species M. cookii. These results suggest that the infectious M432 retroviral genome arose as a result of a recombinational event(s) between the IAP genome and another, as yet unidentified, class of retrovirus-related sequences or other cellular sequences.     

Bacterial lipopolysaccharides form procollagen-endotoxin complexes that trigger cartilage inflammation and degeneration: implications for the development of rheumatoid arthritis

Introduction

We have previously reported that bacterial toxins, especially endotoxins such as lipopolysaccharides (LPS), might be important causative agents in the pathogenesis of rheumatoid arthritis (RA) in an in vitro model that simulates the potential effects of residing in damp buildings. Since numerous inflammatory processes are linked with the nuclear factor-κB (NF-κB), we investigated in detail the effects of LPS on the NF-κB pathway and the postulated formation of procollagen-endotoxin complexes.

Methods

An in vitro model of human chondrocytes was used to investigate LPS-mediated inflammatory signaling.

Results

Immunoelectron microscopy revealed that LPS physically interact with collagen type II in the extracellular matrix (ECM) and anti-collagen type II significantly reduced this interaction. BMS-345541 (a specific inhibitor of IκB kinase (IKK)) or wortmannin (a specific inhibitor of phosphatidylinositol 3-kinase (PI-3K)) inhibited the LPS-induced degradation of the ECM and apoptosis in chondrocytes. This effect was completely inhibited by combining BMS-345541 and wortmannin. Furthermore, BMS-345541 and/or wortmannin suppressed the LPS-induced upregulation of catabolic enzymes that mediate ECM degradation (matrix metalloproteinases-9, -13), cyclooxygenase-2 and apoptosis (activated caspase-3). These proteins are regulated by NF-κB, suggesting that the NF-κB and PI-3K pathways are involved in LPS-induced cartilage degradation. The induction of NF-κB correlated with activation of IκBα kinase, IκBα phosphorylation, IκBα degradation, p65 phosphorylation and p65 nuclear translocation. Further upstream, LPS induced the expression of Toll-like receptor 4 (TLR4) and bound with TLR4, indicating that LPS acts through TLR4.

Conclusion

These results suggest that molecular associations between LPS/TLR4/collagen type II in chondrocytes upregulate the NF-κB and PI-3K signaling pathways and activate proinflammatory activity.     

Structural prediction and comparative docking studies of psychrophilic ��- Galactosidase with lactose, ONPG and PNPG against its counter parts of mesophilic and thermophilic enzymes

Enzymes from psychrophiles catalyze the reactions at low temperatures with higher specific activity. Among all the psychrophilic enzymes produced, cold active β-galactosidase from marine psychrophiles revalorizes a new arena in numerous areas at industrial level. The hydrolysis of lactose in to glucose and galactose by cold active β-galactosidase offers a new promising approach in removal of lactose from milk to overcome the problem of lactose intolerance. Herein we propose, a 3D structure of cold active β-galactosidase enzyme sourced from Pseudoalteromonas haloplanktis by using Modeler 9v8 and best model was developed having 88% of favourable region in ramachandran plot. Modelling was followed by docking studies with the help of Auto dock 4.0 against the three substrates lactose, ONPG and PNPG. In addition, comparative docking studies were also performed for the 3D model of psychrophilic β-galactosidase with mesophilic and thermophilic enzymes. Docking studies revealed that binding affinity of enzyme towards the three different substrates is more for psychrophilic enzyme when compared with mesophilic and thermophilic enzymes. It indicates that the enzyme has high specific activity at low temperature when compared with mesophilic and thermophilic enzymes.     

Long non‐coding RNAs in melanoma

Melanoma is the most lethal cutaneous cancer with a highly aggressive and metastatic phenotype. While recent genetic and epigenetic studies have shed new insights into the mechanism of melanoma development, the involvement of regulatory non‐coding RNAs remain unclear. Long non‐coding RNAs (lncRNAs) are a group of endogenous non‐protein‐coding RNAs with the capacity to regulate gene expression at multiple levels. Recent evidences have shown that lncRNAs can regulate many cellular processes, such as cell proliferation, differentiation, migration and invasion. In the melanoma, deregulation of a number of lncRNAs, such as HOTAIR, MALAT1, BANCR, ANRIL, SPRY‐IT1 and SAMMSON, have been reported. Our review summarizes the functional role of lncRNAs in melanoma and their potential clinical application for diagnosis, prognostication and treatment.     

Changes in odor quality discrimination following recovery from olfactory nerve transection

Following recovery from olfactory nerve transection, animals regain their ability to discriminate between odors. Odor discrimination is restored after new neurons establish connections with the olfactory bulb. However, it is not known if the new connections alter odor quality perception. To address this question, 20 adult hamsters were first trained to discriminate between cinnamon and strawberry odors. After reaching criterion (> or = 90% correct response), half of the animals received a bilateral nerve transection (BTX) and half a surgical sham procedure. Animals were not tested again until day 40, a point in recovery when connections are re-established with the bulb. When BTX animals were tested without food reinforcement, they could not perform the odor discrimination task. Sham animals, however, could discriminate, demonstrating that the behavioral response had not been extinguished during the 40 day period. When reinforcement was resumed, BTX animals were able to discriminate between cinnamon and strawberry after four test sessions. In addition, their ability to discriminate between these two familiar odors was no different than that of BTX and sham animals tested with two novel odors, baby powder and coffee. These findings suggest that, after recovery from nerve transection, there are alterations in sensory perception and that restoration of odor quality discrimination requires that the animal must again learn to associate individual odor sensations with a behavioral response.