Disease relevance of sv

• We report here that 17.6 contains three long open reading frames comparable with gag, pol and env genes in retrovirus [1].
• Better homology existed between another part of the copia open reading frame and a region of the retroviral pol gene recently shown to be distinct from reverse transcriptase and required for the integration of circular DNA forms of the retroviral genome to form proviruses [2].
• It is an A-family DNA polymerase related to Escherichia coli pol I, human POLQ, and Drosophila Mus308 [3].
• Surprisingly, other signaling factors such as Neph-1, Pax2, and Wilms' tumor suppressor-1 appear to work within later fly retinal development, providing a surprising link between these two disparate tissues [4].
• RESULTS: To gain insights into their evolutionary story, a sample of thirteen insect endogenous retroviruses, which represents the largest sample analysed until now, was studied by computer-assisted comparison of the translated products of their gag, pol and env genes, as well as their LTR structural features [5].

High impact information on sv

• In vivo, the majority of TRF1 is complexed with BRF and these two proteins colocalize at many polytene chromosome sites containing RNA pol III genes [6].
• The C4 point mutation of the Drosophila pol II largest subunit confers on the enzyme a lower elongation rate [7].
• The kinetics of recruitment following transcription initiation suggest that the association is with newly transcribed pol II transcripts [8].
• Later, biochemical fractionation led to the co-purification of the multi-subunit Mediator complex and RNA polymerase II (pol II) [9].
• Its three open reading frames encode predicted products resembling the products of the gag, pol and env genes of retroviruses [10].

Biological context of sv

• The ectopic cell death evident in D-Pax2 mutants appears to arise from the cell fate transformation of cone cells into secondary pigment cells, either autonomously or as a result of defective signalling [11].
• D-Pax2 eye phenotypes, in contrast, are dramatically altered in a p35 background, because cells that normally differentiate as cone and primary pigment cells are subsequently transformed into secondary pigment cells [11].
• In addition, we have identified a chimeric element, Uvir, carrying a pol coding sequence only distantly related to sequences thus far found in any telomere arrays [12].
• Also unlike most pol II promoters, the gypsy promoter, which lacks a TATA motif, was found to have an essential sequence at the transcription initiation site, mutation of which abolishes transcription [13].
• These experiments provide the first functional evidence that the small subunit of DNA pol gamma stimulates processive DNA synthesis by the human catalytic subunit under physiological salt conditions [14].

Anatomical context of sv

• Studies on expression and function of key developmental control genes suggest that the embryonic vertebrate brain has a tripartite ground plan that consists of a forebrain/midbrain, a hindbrain and an intervening midbrain/hindbrain boundary region, which are characterized by the specific expression of the Otx, Hox and Pax2/5/8 genes, respectively [15].
• As measured by this assay, neither calf thymus pol delta core enzyme nor PCNA alone bind DNA stably [16].
• In this communication we identify and initially characterize two antagonistic activities in a Xenopus oocyte extract that can modulate the in vitro transcription of RNA polymerase III (pol III) genes (5 S RNA and tRNA genes) [17].
• We show by the use of gene fusion constructs that the subgenomic 2 kilobase copia RNA, encoding gag products, is expressed as protein in cultured cells at least ten-fold more efficiently than the full genome length RNA, which additionally contains the pol and int open reading frames [18].
• During Drosophila embryogenesis, the Pax258 gene is shown to be expressed in the precursor cells of the external sensory organs, thus suggesting a role for Pax258 in the early development of the peripheral nervous system of insects [19].

Associations of sv with chemical compounds

• Results of these studies suggested a model whereby transcription-activator proteins, which bind to specific gene regulatory sequences, recruit both Mediator and pol II as a holoenzyme in a one-step mechanism [9].
• However, our in vitro transcription study reveals that transcription from the human L1 promoter is highly sensitive to tagetitoxin, a selective inhibitor of RNA polymerase III (pol III), but insensitive to 1 micrograms/ml of alpha-amanitin, indicating that the human L1 promoter is pol III-dependent [20].
• The Saccharomyces cerevisiae RAD30 gene encodes a novel eukaryotic DNA polymerase, pol eta that is able to replicate across cis-syn cyclobutane pyrimidine dimers both accurately and efficiently [21].
• We observed new characteristics of Drosophila pol. catalytic subunit as follows: Drosophila pol. catalytic subunit synthesized DNA processively in the presence of both Mn(2+) and Mg(2+) ions, but Mn(2+) inhibited the 3'-5' proofreading activity, thereby decreasing the fidelity of DNA replication by 50% [22].

Other interactions of sv

• Mutational inactivation of otd/Otx2 and unpg/Gbx2 result in the loss or misplacement of the brain-specific expression domains of Pax2/5/8 and Hox genes [15].
• In both cases Wg exerts its effect, at least in part, by negatively regulating the expression of the Pax2 homolog sparkling (spa) [23].
• A second gene, D-Pax2, genetically interacts with lozenge [11].

Analytical, diagnostic and therapeutic context of sv

• To elucidate the functional roles of the spacer region, we pursued deletion and site-directed mutagenesis of Drosophila pol gamma [24].
• A possible role of pol III transcription in mechanisms controlling the expression of full-length mdg1-encoded transcripts in the developing fly, which are apparently relaxed in cell culture, is discussed [25].
• In a previous study, we tried to purify Drosophila pol. catalytic subunit from embryos through seven column chromatographies and study its biochemical properties [22].

References