(n.) A variety of gelatin; the chief ingredient of raw silk, extracted as a white amorphous mass.
Example Sentences:
(1) The 6.2-kilobase (kb) DNA fragment used for the assay, from 5.7 kb upstream to 0.5 kb downstream from the cap site, was end-labeled at the Xho I site (position +514) within the intervening sequence of the fibroin gene.
(2) Their analysis shows that fibroin synthesis is important enough to orient the overall cellular activities.
(3) Transcription of the Bombyx mori fibroin gene in a posterior silk gland extract can be separated into three functional steps on the basis of sensitivity to Sarkosyl: 1) formation of an initiation complex, which is blocked by 0.025% Sarkosyl; 2) conversion of the initiation complex to an elongation complex, a step sensitive to 0.05% Sarkosyl; 3) the subsequent elongation of RNA chain which occurs in the presence of 0.05% Sarkosyl.
(4) The pauses observed during translation generate subsets of smaller discrete peptides, visualized in the gels as ladders of variable relative intensities, appearing exclusively and concomitantly with the fibroin.
(5) 3) In the posterior silk gland, which produces fibroin, the acceptor activities for glycine and alanine increased more than that for serine.
(6) The addition of exogenous histones has an inhibitory effect on fibroin gene transcription in posterior silk gland extracts.
(7) One of these tRNAs appears to be specific to the silk gland, where its accumulation is associated with the rapid production of fibroin.
(8) The increased polysome association of fibroin mRNA and the adequate supply of cognate tRNAs in the 5th instar, together contributes to the translational regulation of fibroin in a developmental stage-specific manner.
(9) The sequence that codes for the gly-ala repetitious peptide characteristic of fibroin begins somewhere between 1340 and 1600 bp from the 5' end.
(10) The alpha 1-tubulin promoter generates about four-fold lower levels, and the fibroin promoter shows no detectable activity in S2 cells.
(11) To clarify the cause of the low transcription efficiency, various chimeric genes were constructed from the actin and fibroin genes, and their transcription efficiencies were examined in vitro.
(12) The patterns of accumulation of fibroin RNA were similar in both the instars.
(13) The fibroin was composed of at least two protein groups of large molecular size and three or four components of small molecular size, and, in addition, a mixture of proteins ranging in size from about 25,000 to more than 100,000 daltons with almost the same amino acid compositions.
(14) In chimeric genes having the actin transcription initiation region and an upstream sequence of the fibroin gene, the transcription efficiency was as low as that of the natural actin gene.
(15) Fibroin mRNA stimulated [3-H]alanine incorporation about 3- to 4-fold in the presence of 80 mM K+ and 4 mM Mg-2+.
(16) About 60% of the fibroin mRNA has a complete cap (m7GpppAmUmCXG), and the remaining 40% has an unmethylated cap (GpppAPyXXG).
(17) The excised cylindrical glands remain metabolically active for several hours in a simple culture medium, where fibroin synthesis can be monitored through the incorporation of 14C alanine.
(18) When the posterior silk gland cell extract is first incubated with pBR322 DNA and then challenged for the fibroin gene transcription on ccc DNA, the pBR322 DNA of the ccc form, but not of the linear one, inhibits the reaction.
(19) In fibroin, only 13% because of its compact beta-pleated sheet structure and low susceptibility to swelling.
(20) This finding, along with saturation hybridization studies (Suzuki, Gage, and Brown, 1972), demonstrate that the fibroin gene is present in a single copy per haploid genome.
Sericin
Definition:
(n.) A gelatinous nitrogenous material extracted from crude silk and other similar fiber by boiling water; -- called also silk gelatin.
Example Sentences:
(1) The onset of the symptoms, with regard to the various stages in the processing of silk, leads one to assume that the allergen involved is sericin.
(2) The sericin gene required more supercoiling for full transcription, whereas no preference for supercoiling was seen with the transcription of hsp70.
(3) Three protein binding sites have been identified in the upstream region of the sericin-1 gene.
(4) The 5' part of one sericin gene had been cloned and described by Okamoto et al.
(5) The UPE of the sericin-1-encoding gene, which is specifically expressed in the middle silk gland, also stimulates Ad2 MLP transcription in a similar manner.
(6) An allatectomy performed on fourth instar larvae promoted production of these mRNAs, suggesting that the synthesis of sericin mRNA is regulated by the titer of juvenile hormone.
(7) Templates containing multimerized SA or SC sites at -39 of the sericin-1 gene promoter were tested in MSG nuclear extracts.
(8) This explains, at least partially, the diversity of the sericins found in the cocoon.
(9) Using nuclear extracts from Bombyx mori middle silk glands (MSG) where the sericin-1 (Ser-1) mRNA is produced specifically, we have studied the in vitro transcription of the Ser-1 gene.
(10) When silk glands of the third instar larvae were transplanted into the abdomen of fifth instar larvae, substantial amounts of sericin mRNAs were induced in the transplant.
(11) The induced sericin gene activity was suppressed upon re-transplantation into the abdomen of fourth instar larvae and induced again when the second hosts grew up to fifth instar larvae.
(12) The sericin gene transcription is mostly restricted to the posterior region of the middle silk gland throughout the fifth larval instar.
(13) SGF-3 is present abundantly in the middle silk gland (MSG) where the sericin-1 gene is transcribed specifically but is also present in other cell types, though in a much less concentration.
(14) Since clusters of homeodomain binding sites can also be found in the promoters of other silk protein genes, the fibroin gene and the sericin-1 gene, these observations suggest a possible involvement of some homeobox genes in the regulation of a group of silk protein genes.
(15) In addition to quantitative adaptation of tRNAs to the composition of silk proteins (fibroin from the posterior silk gland, sericin from the middle part) and of iso-tRNAs from posterior silk gland to the major codons of fibroin mRNA, we also observe adaptation of tRNA from various tissues to the average amino acid content of proteins from fat body, gut, gonads and carcass of the silkworm.
(16) The components of the silk (fibroin and sericin) are also studied (molecular weight, composition).
(17) The middle silkgland cells also express another sericin gene (Ser2) which encodes two mRNA of 5.4 and 3.1 kb, also arising by differential splicing.
(18) Immunological investigations showed clearly that in this context sericin and also antigens from an insect of the genus anthrenus in the silk material are of allergenic importance.
(19) Promoters originating from insect genes, like the Bombyx sericin-1 gene, Drosophila hsp70 and Drosophila copia LTR, functioned as strong promoters in the embryos.
(20) The selective accumulation of tRNAs needed for decoding fibroin and sericin mRNAs which takes place during the Vth larval instar, cannot be explained by the occurrence of a preferential degradation of some tRNA species.