Regulation of gene expression in corn (Zea mays L.) by heat shock. II. In vitro analysis of RNAs from heat-shocked seedlings

1983 ◽  
Vol 61 (6) ◽  
pp. 395-403 ◽  
Author(s):  
Chris L. Baszczynski ◽  
David B. Walden ◽  
Burr G. Atkinson

Five-day-old maize seedlings subjected to heat shock exhibit a dramatic enhancement in the synthesis of a small group of polypeptides. Isolation of total RNA from control and heat-shocked maize plumules, fractionation of poly(A)+ mRNA by oligo(dT)-cellulose chromatography, and in vitro translations of the RNAs in both the rabbit reticulocyte and the wheat germ systems indicates that there is remarkable fidelity of the mRNA pool obtained from heat-shocked plumules to reproduce in vitro those same polypeptides whose synthesis is greatly elevated in the intact, heat-shocked plumule. Moreover, these heat-shock polypeptides with molecular masses of 108 000, 89 000, 84 000, 73 000, and 18 000 are translated from polyadenylated mRNAs. The absence of a 76 000 dalton heat-shock polypeptide (HSP) and the presence of fewer isoelectric point variants of the 89 000 and 84 000 dalton HSPs among the in vitro translation products suggests that translational and (or) posttranslational regulatory mechanisms might be operative in determining the final spectrum of the maize heat-shock proteins.

1984 ◽  
Vol 62 (9) ◽  
pp. 837-846 ◽  
Author(s):  
Herb B. LéJohn ◽  
Cleantis E. Braithwaite

When the temperature of exponentially growing cells of the coenocytic fungus Achlya klebsiana strain 1969 was suddenly elevated from 24 to 37 °C (thermal stress), synthesis of at least 12 preexisting proteins (heat-shock proteins, HSPs) was vigorously induced while synthesis of most other cell proteins declined transiently. After 2–3 h of thermal stress, the cells recovered and resumed normal protein synthesis. If the cells were first starved of nutrients (nutritional stress) before the temperature was raised to 37 °C, the same 12 HSPs were induced, but synthesis of both heat-shock-inducible and nonheat-shock proteins declined to trace levels after 4 h of thermal stress. Molecular weights (MW) of the HSPs were approximately 96 000a, 96 000b, 85 000, 72 000, 70 000, 69 000a, 69 000b, 68 000, 60 000, 52 000, 26 000a, and 26 000b, and they had similar isoelectric points (5.8–6.2). Nutritionally stressed cells showed an induced synthesis of some 28 proteins (nutritional stress proteins, NSPs), when they were not heat shocked, and an induced synthesis of 20 NSPs when heat shocked. In the presence of glutamine, nutritionally stressed cells induced the synthesis of 15 NSPs when they were not heat shocked and 17 NSPs when they were heat shocked. The NSPs and HSPs were electrophoretically different proteins. Glutamine did not affect the induction pattern of the HSPs, but it arrested reproductive development of starving cells while altering the pattern of NSP synthesis. Since actinomycin D inhibited the induced synthesis of HSPs and some NSPs, they may be under transcriptional control. In vitro translation of poly(A)+ RNAs from heat-shocked cells showed that these cells were rich in HSP mRNAs and poor in NSP mRNAs. We speculate that NSPs, but not HSPs, may play a role in reproductive development and sporulation in this fungus.


1985 ◽  
Vol 63 (7) ◽  
pp. 711-722 ◽  
Author(s):  
David Rodenhiser ◽  
Jack H. Jung ◽  
Burr G. Atkinson

Mammalian (human, mouse, and rabbit) white blood cells (lymphocytes) maintained in culture respond to a brief incubation at an elevated temperature (at or above 41 °C) by (i) the new and (or) enhanced synthesis of a small number of proteins (the so-called heat-shock proteins; HSPs) having molecular masses of approximately 110 000, 100 000, 90 000, 70 000, 65 000, and 26 000 daltons and (ii) the depressed synthesis of proteins normally made at 37 °C. The HSPs synthesized in culture by human, rabbit, and mouse (peripheral and splenic) lymphocytes are similar in number, molecular mass, and distribution on two-dimensional (isoelectric focusing and sodium dodecyl sulfate – polyacrylamide) electrophoretic gels to those synthesized in vivo by lymphocytes in hyperthermic mice. Since the level of hyperthermia used to induce HSP synthesis in mouse lymphocytes in vitro and in vivo is of a magnitude (41 °C) also used to promote thermotolerance in mice and is similar to temperatures attained during febrile episodes in rabbits and in humans, we suggest that the in vitro and in vivo synthesis of HSPs by mouse lymphocytes, demonstrated in this study, represents a relevant, physiological response which mammalian lymphocytes may normally use to survive periods of thermal stress.


Author(s):  
R.A. Milligan ◽  
P.N.T. Unwin

A detailed understanding of the mechanism of protein synthesis will ultimately depend on knowledge of the native structure of the ribosome. Towards this end we have investigated the low resolution structure of the eukaryotic ribosome embedded in frozen buffer, making use of a system in which the ribosomes crystallize naturally.The ribosomes in the cells of early chicken embryos form crystalline arrays when the embryos are cooled at 4°C. We have developed methods to isolate the stable unit of these arrays, the ribosome tetramer, and have determined conditions for the growth of two-dimensional crystals in vitro, Analysis of the proteins in the crystals by 2-D gel electrophoresis demonstrates the presence of all ribosomal proteins normally found in polysomes. There are in addition, four proteins which may facilitate crystallization. The crystals are built from two oppositely facing P4 layers and the predominant crystal form, accounting for >80% of the crystals, has the tetragonal space group P4212, X-ray diffraction of crystal pellets demonstrates that crystalline order extends to ~ 60Å.


2005 ◽  
Vol 173 (4S) ◽  
pp. 315-316
Author(s):  
Kari Hendlin ◽  
Brynn Lund ◽  
Manoj Monga

1999 ◽  
Vol 81 (06) ◽  
pp. 951-956 ◽  
Author(s):  
J. Corral ◽  
R. González-Conejero ◽  
J. Rivera ◽  
F. Ortuño ◽  
P. Aparicio ◽  
...  

SummaryThe variability of the platelet GP Ia/IIa density has been associated with the 807 C/T polymorphism (Phe 224) of the GP Ia gene in American Caucasian population. We have investigated the genotype and allelic frequencies of this polymorphism in Spanish Caucasians. The T allele was found in 35% of the 284 blood donors analyzed. We confirmed in 159 healthy subjects a significant association between the 807 C/T polymorphism and the platelet GP Ia density. The T allele correlated with high number of GP Ia molecules on platelet surface. In addition, we observed a similar association of this polymorphism with the expression of this protein in other blood cell types. The platelet responsiveness to collagen was determined by “in vitro” analysis of the platelet activation and aggregation response. We found no significant differences in these functional platelet parameters according to the 807 C/T genotype. Finally, results from 3 case/control studies involving 302 consecutive patients (101 with coronary heart disease, 104 with cerebrovascular disease and 97 with deep venous thrombosis) determined that the 807 C/T polymorphism of the GP Ia gene does not represent a risk factor for arterial or venous thrombosis.


2014 ◽  
Vol 21 (6) ◽  
pp. 564-571 ◽  
Author(s):  
Sourav Roy ◽  
Monobesh Patra ◽  
Suman Nandy ◽  
Milon Banik ◽  
Rakhi Dasgupta ◽  
...  

2018 ◽  
Vol 18 ◽  
Author(s):  
Chaitra Venugopal ◽  
Christopher Shamir ◽  
Sivapriya Senthilkumar ◽  
Janitri Venkatachala Babu ◽  
Peedikayil Kurien Sonu ◽  
...  

Author(s):  
SHREYASHI M ◽  
SULAGNA D ◽  
SANKARI D ◽  
THIRUMURUGAN D ◽  
INFANT SANTHOSE B ◽  
...  

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