Protein synthesis in the salivary glands of Rhynchosciara americana

Winter, Carlos Eduardo; Bianchi, A.G. de; Terra, Walter R.; Lara, Francisco J.

doi:10.1016/0012-1606(80)90139-6

Cited by 17 publications

(5 citation statements)

References 36 publications

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“…A second clone of these sequences, pRal.31, contained a longer cDNA insert and hybridized not only to this 3-kb EcoRI fragment but also to a 6.2-kb fragment. In this experiment we calculated a 16 gives rise to an additional 0.7-kb fragment, which is not seen on this gel.) By comparing the autoradiographic response from microdensitometric tracings of the hybridizing band in the Rhynchosciara DNA with the known amounts of DNA in the plasmid band, it was possible to calculate the number of copies of the cDNA sequences in Rhynchosciara DNA from periods 3 and 6.…”

Section: Resultsmentioning

confidence: 99%

“…As the larvae progress from period 3 to period 4; there is a dramatic change in the pattern of RNA and protein synthesis. This consists of an inhibition of rRNA synthesis (15) and the synthesis of new poly(A)+RNA species (7,8 of new ones (14,16). It is-possible at this time to isolate poly(A)+RNAs from the salivary glands that hybridize in situ to the B2 (8) or the C3 puff(unpublished data).…”

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confidence: 99%

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Gene amplification in Rhynchosciara salivary gland chromosomes.

Glover¹,

Zaha²,

Stocker³

et al. 1982

Proc. Natl. Acad. Sci. U.S.A.

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Late in the fourth larval instar, several regions of the Rhynchosciara amercana salivary gland chromosomes undergo "DNA puffing. " We have constructed a library ofcloned cDNAs synthesized from poly(A)+RNA isolated from salivary glands'during the period ofdevelopment when the DNA puffs are active. From this library we have studied clones representative of three genes active during this period but not active at earlier developmental periods of the gland. One of these genes is not amplified during the developmental process and encodes a 0.6-kilobase RNA molecule. The other two genes are located within the DNA-puffsites C3 and C8and.encode 1.25-kilobase and 1.95-kldobase RNA molecules, respectively. We estimate -from the quantitation -of transfer hybridization experiments that each of these genes undergoes 16-fold amplification during DNA puffing.Gene amplification in somatic cells was first detected by morphological criteria in the larval salivary glands offlies ofthe family Sciaridae. Several regions of the Rhynchosciara americana polytene chromosomes were found to show a type ofpuffing in which, after puff regression, there was more DNA in the bands involved compared with neighboring bands as indicated by Feulgen staining (1). This was later confirmed. both by spectrophotometric measurements (2) and by autoradiographical studies on the incorporation of [3H]thymidine (3). Subsequently, similar observations-were made on the salivary chromosomes of larvae from the genus Sciara (4-6).The DNA puffs, which appear in late fourth instar in-Rhynchosciara salivary glands, are involved in the production of messenger RNAs (7,8). These encode several peptides of the communal cocoon, which are needed in large amounts over a short period of time (9, 10). Based on morphological and physiological criteria, the fourth instar of R. americana larvae has been divided into six periods (11). The first indication of DNA puff formation is the appearance of a fast-green staining band between two orcein (+) bands at the chromosomal sites ofthese puffs early in period 4 (ref. 12; unpublished data). Amplification and puffformation are subsequently maximal at different times for each site and are also dependent on the position of the cell within the gland (13, 14). The largest puffs are found in region 2 of the B chromosome and in regions 3 and 8 of the C chromosome. The B2 puffis formed preferentially in the first 50 cells of the gland in period 5, whereas C3 attains its largest size in the middle and distal section of the gland in period 6. The C8 puff is similar in all regions and is also maximal in period 6. As the larvae progress from period 3 to period 4; there is a dramatic change in the pattern of RNA and protein synthesis. This consists of an inhibition of rRNA synthesis (15) and the synthesis of new poly(A)+RNA species (7,8). This is accompanied by inhibition of the synthesis of certain peptides and the synthesis jtg of unfractionated RNA from the salivary glands of periods 3 and 5 larvae, was fractionated by electrophores...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Gene amplification in Rhynchosciara salivary gland chromosomes.

Glover¹,

Zaha²,

Stocker³

et al. 1982

Proc. Natl. Acad. Sci. U.S.A.

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“…The extent of amplification of the DNA puffs C4 J.C. de-Almeida and B10 of Bradysia hygida was established to be about 22 and 10 times, respectively, for DNA sequences that code for mRNA (6)(7)(8)(9). There is evidence indicating that DNA puff activity is involved in the production of specific proteins in the salivary glands of Rhynchosciara americana (10)(11)(12)(13), Bradysia hygida (14) and Trichosia pubescens (15), some of them being secretory proteins (9,11,12,16,17).…”

Section: Introductionmentioning

confidence: 99%

A 28-fold increase in secretory protein synthesis is associated with DNA puff activity in the salivary gland of Bradysia hygida (Diptera, Sciaridae)

Jc¹

1997

Braz J Med Biol Res

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A 28-fold increase in secretory protein synthesis is associated with DNA puff activity in the salivary gland of Bradysia hygida (Diptera, Sciaridae) AbstractWhen the first group of DNA puffs is active in the salivary gland regions S1 and S3 of Bradysia hygida larvae, there is a large increase in the production and secretion of new salivary proteins demonstrable by [ 3 H]-Leu incorporation. The present study shows that protein separation by SDS-PAGE and detection by fluorography demonstrated that these polypeptides range in molecular mass from about 23 to 100 kDa. Furthermore, these proteins were synthesized mainly in the S1 and S3 salivary gland regions where the DNA puffs C7, C5, C4 and B10 are conspicuous, while in the S2 region protein synthesis was very low. Others have shown that the extent of amplification for DNA sequences that code for mRNA in the DNA puffs C4 and B10 was about 22 and 10 times, respectively. The present data for this group of DNA puffs are consistent with the proposition that gene amplification is necessary to provide some cells with additional gene copies for the production of massive amounts of proteins within a short period of time (Spradling AC and Mahowald AP (1980) Proceedings of the National Academy of Sciences, USA, 77: 1096-1100).

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“…As células de toda a glândula, independente da região, tanto no 2º período do desenvolvimento quanto no início da construção do casulo comunal, apresentam-se repletas de retículo endoplasmático rugoso. Fica claro, como já observado em outros trabalhos, que a glândula salivar tem papel fundamental na produção da secreção que irá construir o casulo comunal (WINTER et al, 1977a, b;1980). A proteína LC3 também é encontrada na fase de pupa no corpo gorduroso.…”

Section: Radadunclassified

Aspectos celulares e moleculares das glândulas salivares e do corpo gorduroso de Rhynchosciara americana durante o desenvolvimento.

Brandão¹

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Protein synthesis in the salivary glands of Rhynchosciara americana

Cited by 17 publications

References 36 publications

Gene amplification in Rhynchosciara salivary gland chromosomes.

Gene amplification in Rhynchosciara salivary gland chromosomes.

A 28-fold increase in secretory protein synthesis is associated with DNA puff activity in the salivary gland of Bradysia hygida (Diptera, Sciaridae)

Aspectos celulares e moleculares das glândulas salivares e do corpo gorduroso de Rhynchosciara americana durante o desenvolvimento.

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