Hemoglobin messenger ribonucleic acid. Synthesis of 9 S and ribosomal ribonucleic acid during erythroid cell development

Biochemistry ◽  
1969 ◽  
Vol 8 (7) ◽  
pp. 3000-3005 ◽  
Author(s):  
Michael J. Evans ◽  
Jerry B. Lingrel
Keyword(s):  
Ribonucleic Acid ◽  
Acid Synthesis ◽  
Cell Development ◽  
Erythroid Cell ◽  
Messenger Ribonucleic Acid ◽  
Ribosomal Ribonucleic Acid

scholarly journals Rate of synthesis and half-life of globin messenger ribonucleic acid. Rate of synthesis of globin messenger ribonucleic acid calculated from data of cell haemoglobin content

1974 ◽  
Vol 138 (3) ◽  
pp. 499-510 ◽  
Author(s):  
John A. Hunt
Keyword(s):  
Ribonucleic Acid ◽  
Half Life ◽  
Chain Elongation ◽  
Erythroid Cell ◽  
Synthesis Rate ◽  
Mrna Synthesis ◽  
Base Pairs ◽  
Messenger Ribonucleic Acid ◽  
Nucleotide Base ◽  
Mrna Half Life

By the use of the favoured models defining mRNA synthesis and half-life from the preceding paper (Hunt, 1974) and the known content of globin in a reticulocyte it is possible to estimate the absolute rate of mRNA and globin synthesis and the mRNA and globin content in each type of erythroid cell. The best model requires an mRNA-synthetic rate of 3000 molecules per h/cell. This rate compares favourably with the estimated chain-extension rate of 43 nucleotides/s in Escherichia coli (Manor et al., 1969) provided that the four α- and β-chain cistrons per cell are transcribed by polymerases spaced 50 nucleotide base pairs apart. Similar calculations can be made for erythropoiesis in the chick embryo, where cell times and relative globin content at each mitosis have been measured (Campbell et al., 1971), but where no reliable estimates of mRNA half-life have been made. In this case it was estimated that a constant rate of mRNA synthesis at 10000 molecules per h/cell through six cell divisions is necessary if the mRNA half-life is 15h; after the sixth mitosis the mRNA synthesis would stop and its half-life would increase to approx. 20h. If an mRNA half-life of 4.5h is used, the synthesis rate through the six mitoses would be 21000 molecules per h/cell, ceasing at the sixth mitosis, when the half-life would need to increase to 25h. The chain-elongation rate for the four α- and β-globin cistrons per cell would be 1–2 times higher than in E. coli and would either require a greater rate, polymerases spaced between 25 and 50 nucleotide base pairs apart on the DNA, or limited gene replication. These possibilities are discussed in the light of the low values found for globin cistron multiplicity in ducks and mice.

Thyroid Hormone Regulation of α-Lactalbumin: Differential Glycosylation and Messenger Ribonucleic Acid Synthesis in Mouse Mammary Glands

Endocrinology ◽  
1988 ◽  
Vol 123 (5) ◽  
pp. 2242-2248 ◽  
Author(s):  
S. E. ZISKA ◽  
M. BHATTACHARJEE ◽  
R. L. HERBER ◽  
P. K. QASBA ◽  
B. K. VONDERHAAR
Keyword(s):  
Thyroid Hormone ◽  
Ribonucleic Acid ◽  
Acid Synthesis ◽  
Mammary Glands ◽  
Hormone Regulation ◽  
Messenger Ribonucleic Acid

scholarly journals Activating Mutations of the Gsα Gene Are Associated with Low Levels of Gsα Protein in Growth Hormone-Secreting Tumors1

1998 ◽  
Vol 83 (12) ◽  
pp. 4386-4390 ◽  
Author(s):  
Emilia Ballaré ◽  
Simona Mantovani ◽  
Andrea Lania ◽  
Anna M. Di Blasio ◽  
Lucia Vallar ◽  
...  
Keyword(s):  
Cholera Toxin ◽  
Ribonucleic Acid ◽  
Pituitary Tumors ◽  
Acid Synthesis ◽  
Endocrine Tumors ◽  
Wild Type ◽  
Messenger Ribonucleic Acid ◽  
Activating Mutations ◽  
Gsα Gene ◽  
System Data

Evidence suggests the existence of a direct relationship between cellular Gsα content and activation of the adenylyl cyclase system. Data on Gsα levels in endocrine tumors that depend on cAMP for growth, particularly pituitary adenomas, are still limited. The levels of Gsα protein were evaluated in 11 GH-secreting adenomas with Gsα mutations (gsp+) and 15 without (gsp). Complementary DNAs from gsp+ tumors contained very low amounts of wild-type Gsα sequences, indicating a preponderance of the mutant Gsα transcripts in these tumors. Immunoblotting of Gsα protein showed that the two isoforms were present at high levels in all gsp−, but were undetectable or barely detectable in gsp+. The low Gsα content in gsp+ tumors was not due to a reduction in ribonucleic acid synthesis or stability, as Gsα messenger ribonucleic acid levels were similar in wild-type and mutant tissues. Treatment of gsp− cells with cholera toxin caused a marked reduction of Gsα levels. As in other cell systems cholera toxin increases Gsα degradation, our data are consistent with an accelerated removal of mutant Gsα. This may represent an additional mechanism of feedback response to the constitutive activation of cAMP signaling in pituitary tumors with mutations in the Gsα gene.

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