Q8312967
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Genetické modifikace (GM) hmyzu zahrnují řadu metod vedoucích k odstranění (umlčení) určitého genu (nejčastěji pomocí RNAi, nebo knockouť genu) nebo vnesení cizorodého genu (hlavně pomocí transpozonů, z nichž je nejznámější systém P-elementů). V obou případech se úspěšnost GM sleduje pomocí exprese „marker" genů (dnes většinou „green fluorescent protein"). Pro drozofilu jsou dostupné další techniky a zejména velké banky různých mutací. Systém cis elementu UAS („Upstream Activation Sequence") a jeho aktivátoru Gal4 umožňuje exprimovat vnesený gen v určitých buňkách či orgánech. Genetické modifikace u drozofily i dalších modelových druhů hmyzu se používají jako prostředek pro objasnění vývojových a fyziologických regulací, včetně poruch, které napodobují lidská onemocnění. GM mohou také omezit rozmnožování, nebo způsobit úhyn škodlivého hmyzu. Tato technika by však vyžadovala vypouštění GM hmyzu do přírody a to je v současnosti nemožné. Prakticky významné jsou však GM využívané v chovech hmyzu, který je po sterilizaci vypouštěn do přírody, aby svým přečíslením podstatně snížil rozmnožování přírodní populace (tzv. „sterile insect technice", SIT).
Genetic modifications of insects include diverse methods of gene silencing, such as gene knockdown or RNAi, and methods of transgenesis when a foreign gene is introduced into insect genome, usually with the aid of transponsons such as the P elements. The success of GM is typically visualized through expression of a gene encoding the green fluorescent protein or another marker. Additional techniques and also large banks of diverse mutations are available for drosophila. The system of UAS (Upstream Activation Sequence) and its transcription activator Gal4 allows in this species transgene expression in certain cells and organs. Genetic modifications of drosophila and other model insect species provide efficient tool for elucidating developmental and physiological regulations, including defects mimicking human diseases. GM can also be used to curb insect reproduction or survival. Practical deployment of this approach, however, would require release of GM insects into the environment and this would hardly be permitted. On the other hand, GMs restricted to insect cultures are practically exploited in the sterile insect technique (SIT), when sterilized, non-GM insects are released into the field and due to their high numbers and random mating suppress the growth of the native wild population.
- Klíčová slova
- umlčení genů, transgeneze, P-elementy, Piggy bag, GFP, UAS/Gal4, vypouštění sterilních samců,
- MeSH
- financování organizované MeSH
- geneticky modifikovaná zvířata genetika MeSH
- hmyz genetika MeSH
- regulace genové exprese genetika MeSH
- RNA interference MeSH
- technika přenosu genů MeSH
- transgeny fyziologie genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
Sericins are soluble silk components encoded in Bombyx mori by three genes, of which Ser1 and Ser3 have been characterized. The Ser1 and Ser3 proteins were shown to appear later in the last larval instar as the major sericins of cocoon silk. These proteins are, however, virtually absent in the highly adhesive silk spun prior to cocoon spinning, when the larvae construct a loose scaffold for cocoon attachment. We show here that the silk-gland lumen of the feeding last instar larvae contains two abundant adhesive proteins of 230 kDa and 120 kDa that were identified as products of the Ser2 gene. We also describe the sequence, exon-intron structure, alternative splicing and deduced translation products of this gene in the Daizo p50 strain of B. mori. Two mRNAs of 5.7 and 3.1 kb are generated by alternative splicing of the largest exon. The predicted mature proteins contain 1740 and 882 amino acid residues. The repetitive amino acid sequence encoded by exons 9a and 9b is apparently responsible for the adhesiveness of Ser2 products. It has a similar periodic arrangement of motifs containing lysine and proline as a highly adhesive protein of the mussel Mytilus edulis.
Inhibitory activity against subtilisin, proteinase K, chymotrypsin and trypsin was detected in the salivary glands and saliva of the cockroach Nauphoeta cinerea (Blattoptera: Blaberidae). Fractionation of the salivary glands extract by affinity chromatography followed by reverse-phase HPLC yielded five subtilisin-inhibiting peptides with molecular masses ranging from 5 to 14 kDa. N-terminal sequences and subsequently full-length cDNAs of inhibitors designated NcPIa and NcPIb were obtained. The NcPIa cDNA contains 216 nucleotides and encodes a pre-peptide of 72 amino-acid residues of which 19 make up the signal peptide. The cDNA of NcPIb consists of 240 nucleotides and yields a putative secretory peptide of 80 amino-acid residues. Mature NcPIa (5906.6 Da, 53 residues) and NcPIb (6713.3 Da, 60 residues) are structurally similar (65.4% amino acid overlap) single-domain Kazal-type peptidase inhibitors. NcPIa with Arg in P1 position and typical Kazal motif VCGSD interacted stoichiometrically (1:1) with subtilisin and was slightly less active against proteinase K. NcPIb with Leu in P1 and modified Kazal motif ICGSD had similar activity on subtilisin and no on proteinase K but was active on chymotrypsin.
- MeSH
- inhibitory proteas metabolismus MeSH
- molekulární sekvence - údaje MeSH
- proteasy metabolismus MeSH
- regulace genové exprese MeSH
- sekvence aminokyselin MeSH
- sekvence nukleotidů MeSH
- švábi metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
