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Pre-mRNAs are associated with hnRNPs, and these proteins play important roles in the biogenesis of mRNAs. The hnRNP A1 is one of the most abundant hnRNPs, and although localized primarily in the nucleoplasm, shuttles continuously between the nucleus and the cytoplasm. A 38 amino acid domain within A1, termed M9, which bears no resemblance to classical nuclear localization signal (NLS) sequences, localizes A1 to the nucleus. Here we show that M9 is also a nuclear export signal; placing M9 on a protein that is otherwise restricted to the nucleus, the nucleoplasmin core domain (NPc), efficiently exports it to the cytoplasm in a temperature-dependent manner. In contrast, classical NLSs cannot promote the export of NPc. These findings demonstrate that there is a signal-dependent, temperature-sensitive nuclear export pathway and strengthen the suggestion that A1 and other shuttling hnRNPs function as carriers for RNA during export to the cytoplasm.

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ObjectivesIdentify the characteristics related to the suicide rates in rural and urban areas of Korea and discover the factors that influence the suicide rate of the rural and urban areas.MethodsUsing the data on causes of death from 2006 to 2008, the suicide rates were calculated and compared after age-standardization based on gender, age group and urbanicity. And, in order to understand the factors that influence suicide rate, total 10 local characteristics in four domains - public service, social integration, residential environment, and economic status - were selected for multiple regression analysis.ResultsThe suicide rates were higher in men than women, in rural areas than urban, and in older people than the younger. Generally, although there were variations according to age group and urbanicity, suicide rates were significantly related to residential environment and regional economic status but not related to regional welfare spending and social integration. In addition, the population over the age of 65 years, only regional economic status has significantly influence on their suicide rates.ConclusionsThe influence of characteristics of regions on suicide rate is various by age-group, gender, and urbanicity. Therefore, in order to lower suicide rate and reduce the gap between regions, various approaches must be adopted by taking into account the socioeconomic characteristics of the regions.

The inhibition of mushroom tyrosinase by methanolic extract of Dictyophora indusiata was evaluated and the bioactive component was characterized and identified as 5-(hydroxymethyl)-2-furfural (HMF) by chromatographic and spectroscopic means. Kinetic studies revealed it to be a noncompetitive inhibitor for the oxidation of L-DOPA. On the basis of these findings some related analogues were also tested for their anti-tyrosinase activity, in order to gain more insight into structure and activity relationship among these heterocyclic compounds.

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The coliphage N4-coded single-stranded DNA-binding protein (N4SSB) is essential for phage replication and for expression of the phage late genes, which are transcribed by the Escherichia coli 70 RNA polymerase. As a first step in investigating the role of N4SSB in replication and transcriptional activation, we have identified and sequenced the N4SSB gene. The gene encodes a 265-amino acid protein with no apparent sequence homology to other single-stranded DNA-binding proteins. We present data indicating that N4SSB is also essential for phage recombination. Mutational analysis of the carboxyl terminus of the protein indicates that this region is required for protein-protein interactions with the N4 replication, N4 recombination, and E. coli transcriptional machineries, while the rest of the protein contains the determinants for single-stranded DNA binding.Proteins that bind nonspecifically to single-stranded DNA with high affinity have been purified and characterized from several sources (1, 2). Single-stranded DNA-binding proteins are present in high concentration in vivo and are essential components in a variety of DNA metabolism processes. They are required for DNA replication and are also involved in repair and recombination (1). They bind to single-stranded DNA stoichiometrically and, in most cases, with positive cooperativity (3).The N4-coded single-stranded DNA-binding protein (N4SSB) 1 was originally detected as an activity capable of complementing the defect of mutant phage N4am7 in replication (4). The purified protein has a monomer M r of 32,000 and binds single-stranded DNA more tightly than RNA, with a binding site size of 11 nucleotides, an intrinsic binding constant of 3.8 ϫ 10 4 M Ϫ1 , and a cooperativity of 300 ( ) in 0.22 M NaCl at 37°C (5). Although N4SSB is able to lower the melting transition of poly(dA)⅐poly(dT) by at least 60°C, it cannot lower the melting transition or assist in the renaturation of natural DNAs. In vitro, N4SSB specifically stimulates the N4 DNA polymerase by increasing its processivity 300-fold and by melting out hairpin structures that block polymerization (5). Surprisingly, N4SSB is also required for the synthesis of N4 late RNAs, which is catalyzed by the Escherichia coli 70 RNA polymerase (6). In vitro, N4SSB allows E. coli 70 RNA polymerase to utilize efficiently N4 late promoters (6). Therefore, in addition to playing an essential role in N4 DNA replication, N4SSB is a transcriptional activator, suggesting that it is a multifunctional protein. To dissect the domains of N4SSB responsible for activation of N4 DNA polymerase on a primed template and of E. coli 70 RNA polymerase at N4 late promoters, we cloned and sequenced the gene encoding N4SSB and constructed an N4SSB expression vector. Expression of the cloned protein complemented N4am7 phage, carrying a mutation in the N4SSB gene, for N4 DNA replication and late transcription. Additionally, we have found that N4SSB is essential for N4 DNA recombination. Analysis of the different phenotypes of carboxyl-terminal del...