Developmental expression of FOG-1/CPEB protein and its control in the Caenorhabditis elegans hermaphrodite germ line.

The specification of a germ cell as sperm or oocyte and determination of cell number remain unsolved questions in developmental biology. This paper examines Caenorhabditis elegans FOG-1, a CPEB-related RNA-binding protein that controls the sperm fate. We find that abundant FOG-1 protein is observed transiently in germ cells just prior to their expression of an early sperm-differentiation marker. As the germline tissue elongates, abundant FOG-1 appears more and more distally as sperm become specified, but disappears when the germ line switches to oogenesis. This dynamic pattern is controlled by both globally acting and germline-specific sex-determining regulators. Importantly, the extent of FOG-1 expression corresponds roughly to sperm number in wild-type and mutants, altering sperm number. By contrast, three other key regulators of the sperm/oocyte decision do not similarly correspond to sperm number. We suggest that FOG-1 is precisely modulated in both time and space to specify sperm fate and control sperm number.     

The exclusion among the Ustilago viruses — A dsRNA restriction modification system?

Summary Specific exclusion relations are know among the three Ustilago maydis viruses that are associated with the cytoplasmically transmitted killer phemomenon. Of the three viruses P1, P4 and P6, only P1, and P4 cancoexist in one host cell. Mutual exclusion occurs between P1 and P6 and P4 unilaterally excludes P6. The exclusion relations were originally defined among the wild-type viruses. Those relations can be modified by two specific segments that are a part of the P4 dsRNA genome and were also found in some sensitive strains that contained part of the viral genome. Also, deletion of the dsRNA segment that is assumed to encode the toxin information permits the formation of hybrid genomes that otherwise cannot be formed. The data is interpreted in terms of a dsRNA restriction modification system in which the killer toxin or a toxin-linked function acts as the restriction factor and segments H3 and H4 or H4 alone contain the necessary information for the modification of certain sites on the M and L segments of the P1 and P4 viruses but not on the P6 segments.     

Effect of double-stranded RNA and type I interferons on cytomegalovirus reproduction in human fibroblasts

D. I. Ivanovskii Institute of Virology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR D. K. L'vov) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 112, No. 7, pp. 80–83, July, 1991.     

Ontogenetic development of proenkephalin A and proenkephalin B messenger RNA in fetal pigs

Summary Using solution hybridization analysis and Northern blotting with complementary RNA probes labelled to high specific activity, levels of proenkephalin A and B mRNA were analyzed throughout prenatal development in the hippocampus and striatum of fetal pigs. A differential time course for the appearance of these opioid precursor mRNAs was observed: in hippocampus, both mRNAs increased linearly throughout development with proenkephalin B mRNA increasing faster than proenkephalin A mRNA. In striatum, both mRNAs behaved similarly, increasing to a maximum level around mid-gestation and declining thereafter. The differences might be attributed to differential localization of the two precursor systems in the tissues and might be of functional relevance.Abberviations PENK A, PENK B Proenkephalin A, B - mRNA Messenger Ribonucleic Acid - cRNA Complementary RNA     

The asymmetries in morphology, desoxyribonucleic acid, protein and ribonucleic acid of the two hemispheres induced by monolateral removal of the olfactory bulb and retrobulbar structures in neonatal rats

Monolateral removal of the olfactory bulb and the olfactory penduncular structures in the neonatal rat resulted in a profound morphological and biochemical asymmetry between the two hemispheres. The experimental hemisphere, ipsilateral to the lesion, protruded into the space normally occupied by the olfactory bulb and showed enlarged ventricles. The brain loci were displaced rostrally in this hemisphere.The desoxyribonucleic acid, ribonucleic acid and protein contents of the experimental hemisphere at 25 and 60 days of age were all significantly lower than that found in the control hemisphere contralateral to the lesion.To resolve between the two possible causes of this asymmetry (i.e. atrophy of the experimental or hypertrophy of the control hemisphere) hemispheres of the asymmetric brain were compared with homonymous hemispheres of unoperated normal rats. This comparison revealed that the asymmetry is basically due to an excess of desoxyribonucleic acid synthesis in the control hemisphere, which continues even after postnatal day 25, on the one hand, and a dearth of protein in the experimental hemisphere on the other. This finding implies two separate mechanisms for the processes that underlie the asymmetries observed for these two substances.Our results demonstrate two important characteristics of the developing brain. Firstly they indicate that removal of the olfactory bulb and the olfactory peduncle can produce considerable changes in the hemispheres, and secondly they unravel the strong latent potential of the brain for cell proliferation beyond the usual period of cell division in the brain. As in these experiments regulation of cell division is affected, this system might serve as a model for the study of aberrant cell division found in tumor formation and the process of carcinogenesis.     

Chromatin interactions in differentiating keratinocytes reveal novel atopic dermatitis– and psoriasis-associated genes

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Comprehensive analysis of key lncRNAs in HCV-positive hepatocellular carcinoma

IntroductionHepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Despite the therapeutic advances in HCC in the past few decades, the mortality rate of HCC is still high. Hepatitis C (HCV) infection is one of the major etiological risk factors of HCCs. However, the underlying mechanisms of HCV-induced hepatocarcinogenesis remain largely unclear.Material and methodsOur study represented the comprehensive analysis of differentially expressed lncRNAs in HCV-positive HCC for the first time by analyzing the public dataset {"type":"entrez-geo","attrs":{"text":"GSE17856","term_id":"17856"}}GSE17856. Co-expression network and gene ontology (GO) analysis revealed the functions of those differentially expressed lncRNAs.ResultsWe identified 256 upregulated lncRNAs and 198 downregulated lncRNAs in HCV- positive HCC compared to the normal liver tissues. Co-expression network and GO analysis showed that these lncRNAs were involved in regulating metabolism, energy pathways, proliferation and the immune response. Seven lncRNAs (LOC341056, CCT6P1, PTTG3P, LOC643387, LOC100133920, C3P1 and C22orf45) were identified as key lncRNAs and co-expressed with more than 100 differentially expressed genes (DEGs) in HCV-related HCC. Kaplan-Meier analysis showed that higher expression levels of LOC643387, PTTG3P, LOC341056, CCT6P1 and lower expression levels of C3P1 and C22orf45 were associated with shorter survival time in the TCGA dataset.ConclusionsWe believe that this study can provide novel potential therapeutic and prognostic biomarkers for HCV-positive HCC.     

The ribosomal DNA of the Zygomycete Mucor miehei

The ribosomal DNA from the Zygomycete Mucor miehei has been characterised. The complete rDNA unit was cloned by heterologous PCR using primers whose sequence matched conserved regions of the rDNA from related fungal species. The sequence of the overlapping PCR products revealed the existence of a repeated unit of 9574 bp. The genes encoding the different rRNA species were identified by their homology to the corresponding sequences from other fungi. We estimate that the rDNA unit is present in the genome of M. miehei in about 100 copies. This estimation was made by comparing the intensity of its hybridisation signal in a Southern blot with that of the mmp gene coding for aspartyl protease, which was assumed to be contained in single copy. The size and structure of the M. miehei rDNA unit was similar to that of other fungi. The genes encoding the 25S, 18S and 5.8S RNAs are closely linked within the repeated unit which also contains the 5S gene. This latter gene appears to be transcribed in the opposite direction. The 25S, 18S and 5.8S genes showed 70–80% homology to the corresponding genes from other fungi, whereas the degree of homology for the 5S gene was much lower. The highest homology (about 80%) corresponded to the few available sequences from other Mucor species. Homology to genes from other Zygomycota was no higher than that observed for genes from the Ascomycota or Basidiomycota fungi. Received: 21 December 1999 / 1 March 2000