Peripheral Nervous System Genes Expressed in Central Neurons Induce Growth on Inhibitory Substrates

Trauma to the spinal cord and brain can result in irreparable loss of function. This failure of recovery is in part due to inhibition of axon regeneration by myelin and chondroitin sulfate proteoglycans (CSPGs). Peripheral nervous system (PNS) neurons exhibit increased regenerative ability compared to central nervous system neurons, even in the presence of inhibitory environments. Previously, we identified over a thousand genes differentially expressed in PNS neurons relative to CNS neurons. These genes represent intrinsic differences that may account for the PNS’s enhanced regenerative ability. Cerebellar neurons were transfected with cDNAs for each of these PNS genes to assess their ability to enhance neurite growth on inhibitory (CSPG) or permissive (laminin) substrates. Using high content analysis, we evaluated the phenotypic profile of each neuron to extract meaningful data for over 1100 genes. Several known growth associated proteins potentiated neurite growth on laminin. Most interestingly, novel genes were identified that promoted neurite growth on CSPGs (GPX3, EIF2B5, RBMX). Bioinformatic approaches also uncovered a number of novel gene families that altered neurite growth of CNS neurons

Иксодовые клещи юга Восточной Сибири и Монголии и их спонтанная зараженность возбудителями природно-очаговых трансмиссивных инфекций

The goal of the study is to reveal the species of Ixodid ticks in Eastern Siberia and Mongolia, having epidemiological value and pathogens that transmit to humans via their bites. The tasks is to determine ecologo-epidemiologial characteristics of the main vectors and genetic characteristics of the agents of tick-borne infections. Characterization of the materials. There are materials of the study of more than 200 000 Ixodid ticks of 4 species and their rate of infection by different pathogens with zooparasitological, epidemiological, virological, microbiological, molecular-biological standard and modified to the goals and tasks of the study. Most abundance and dangerous species is Ixodes persulcatus P.Sch. ticks, that is widespread in region investigated. The agents of known vector-borne infections in Eastern Siberia and Mongolia are tick-borne encephalitis virus, Borrelia garinii, Borrelia afze- lii, Rickettsia sibirica, R. sp. DnS14 group.C целью выявления видов иксодовых клещей, имеющих эпидемическое значение на территории Восточной Сибири и Мон- голии, и возбудителей инфекций, передающихся человеку через их укусы, были исследованы эколого-эпидемиологические и ге- нетические характеристики основных переносчиков клещевых инфекций и связанных с ними возбудителей болезней человека. В статье приведены материалы изучения более 200 тыс. экземпляров иксодовых клещей четырех видов, исследован- ных при помощи общепринятых зоопаразитологических, эпидемиологических, вирусологических, микробиологических, молекулярно-биологических и модифицированных применительно к целям и задачам исследования методов. Наиболее массовым и опасным видом является таежный клещ Ixodes persulcatus P. Sch., широко распространенный в регионе. Эпидемиологическое значение имеют также клещи видов Dermacentor nuttalli Ol., Dermacentor silvarum Ol., Hae- maphysalis concinna Koch. Возбудителями трансмиссивных инфекций в Восточной Сибири и Монголии являются вирус КЭ, боррелии, риккетсии, возможно, эрлихии и другие патогены

Insights into the evolution of mammalian telomerase: Platypus TERT shares similarities with genes of birds and other reptiles and localizes on sex chromosomes

Background The TERT gene encodes the catalytic subunit of the telomerase complex and is responsible for maintaining telomere length. Vertebrate telomerase has been studied in eutherian mammals, fish, and the chicken, but less attention has been paid to other vertebrates. The platypus occupies an important evolutionary position, providing unique insight into the evolution of mammalian genes. We report the cloning of a platypus TERT (OanTERT) ortholog, and provide a comparison with genes of other vertebrates. Results The OanTERT encodes a protein with a high sequence similarity to marsupial TERT and avian TERT. Like the TERT of sauropsids and marsupials, as well as that of sharks and echinoderms, OanTERT contains extended variable linkers in the N-terminal region suggesting that they were present already in basal vertebrates and lost independently in rayfinned fish and eutherian mammals. Several alternatively spliced OanTERT variants structurally similar to avian TERT variants were identified. Telomerase activity is expressed in all platypus tissues like that of cold-blooded animals and murine rodents. OanTERT was localized on pseudoautosomal regions of sex chromosomes X3/Y2, expanding the homology between human chromosome 5 and platypus sex chromosomes. Synteny analysis suggests that TERT co-localized with sex-linked genes in the last common mammalian ancestor. Interestingly, female platypuses express higher levels of telomerase in heart and liver tissues than do males. Conclusions OanTERT shares many features with TERT of the reptilian outgroup, suggesting that OanTERT represents the ancestral mammalian TERT. Features specific to TERT of eutherian mammals have, therefore, evolved more recently after the divergence of monotremes.Radmila Hrdličková, Jiří Nehyba, Shu Ly Lim, Frank Grützner, Henry R Bose J

Assignment1 of the DMRT1 gene to tammar wallaby chromosome 3p by fluorescence in situ hybridization

N. El-Mogharbel, J. Deakin, E. Tsend-Ayush, A. Pask and J.A.M. Grave

Evolution and organization of the ten sex chromosome system in platypus

Platypus sex chromosomes have been controversial for over three decades. To solve the platypus chromosome puzzle we have generated whole chromosome paints for all platypus chromosomes. Hybridization on mitotic chromosomes of males and females and male meiotic cells revealed that platypus have five Ys and five X chromosomes, which form the meiotic chain adopting an XY alternating pattern. With remarkable accuracy the chain segregates into XXXXX-female determining and YYYYY-male determining sperm. The largest X chromosome, with homology to the human X, lies at one end of the chain (X1). At the other end of the chain we mapped the gene DMRT1 onto X5. DMRT1 is a Z-linked candidate sex-determining gene in chicken. This suggests an unexpected link between mammal and bird sex chromosome systems that were thought to have evolved independently. Moreover we found that Y1 is not very degraded and shares significant homology with the short arm of X1, indicating that X1Y1 is the most recent addition to the chain. In contrast, the tiny Y5 at the other end of the chain is very degraded and X5 showed no detectable homology with Y5. Therefore we conclude that X5Y5 is the original sex chromosome pair. Using the paints and sex chromosome specific BAC clones we have analyzed meiotic chromatin condensation and chromosome pairing of the ten sex chromosomes in platypus. Our results show that, as in other mammals, platypus sex chromosomes are condensed and pair late at pachytene, indicating that meiotic sex chromosome inactivation may occur as in other mammals