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5 záznamů v Medvik

Článek

Structure and expression of the silk adhesive protein Ser2 in Bombyx mori

Insect biochemistry and molecular biology. 2009 ; 39 (12) : 938-946. [pub] 20091206

Insect Biochem Mol Biol
ISSN 1879-0240
Medvik
Zdroj

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.

Abstrakt

What can a fly tell us about human physiology and pathophysiology?

Physiological research. 2009 ; 58 (3) : 15P.

ISSN 0862-8408
Medvik
Zdroj

Publikační typ
abstrakty MeSH

Článek

Use of two transcription starts in the G6PD gene of the bark beetle Ips typographus

Insect molecular biology. 2006 ; 15 (1) : 25-32.

ISSN 0962-1075
Medvik
Zdroj

The enzyme glucose-6-phosphate dehydrogenase (G6PD) of the bark beetle Ips typographus is derived from a gene that includes eight exons and spans over 7100 nucleotides (nt). By means of two transcription starts, the gene generates two mRNA isoforms that are present in similar amounts in the larvae, pupae and adults. The A isoform includes exon IA of 115 nt, which is followed by intron 1a extending to position 3457 of the gene. The B mRNA isoform begins with exon IB (100 nt) that occupies positions 3291-3390 within the 1a intron. Exons II to VII are included in both mRNA isoforms. The gene contains 31.6% (36.5% in the translated region) of the GC nucleotides. Two transcription starts and the exon/intron organization distinguish bark beetle G6PD from the homologous genes known in other insects. Two enzyme variants were detected in the protein extracts of individual bark beetles but their relationship to the A and B mRNA isoforms is uncertain.