Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The expression of mRNAs for two cardiac myosins has been studied in the ventricles of hypo- and hyperthyroid rabbits by using cloned cDNA sequences corresponding to the mRNAs of the alpha- and beta-myosin heavy chains (HCs). The temporal change in relative levels of the alpha and beta HC mRNAs after triiodothyronine (T3) treatment of hypothyroid rabbits was determined by nuclease S1 mapping. In the hypothyroid state, only NC beta-mRNA was expressed in the ventricles. The HC alpha-mRNA was first detectable 4 h after administration of T3 (200 micrograms/kg) to hypothyroid animals. By 12, 24, and 72 h, HC alpha-mRNA represented 20, 50, and 90% of total myosin mRNA. The relationship between the relative mRNA levels and relative synthesis rates of myosin HCs was evaluated in 5- to 6-wk-old normal and thyrotoxic rabbits. Myosin synthesis rates were determined by labeling of protein in vivo with [2H]leucine. The V1 (HC alpha) and V3 (HC beta) isomyosins were separated by immune affinity chromatography and the HCs were isolated electrophoretically. In a normal euthyroid group of animals and in animals 12 and 24 h after administration of 200 micrograms of thyroxine, the relative mRNA levels and relative synthesis rates of the alpha and beta HCs were not significantly different. Our results show that, first, thyroid hormone causes a rapid accumulation of HC alpha-mRNA and loss of HC alpha-mRNA, and second, in normal and thyrotoxic rabbits, the relative synthesis rates of HC alpha and HC beta reflect the relative abundance of their respective mRNAs. These data are consistent with the thyroid hormones regulating synthesis of ventricular myosin at steps that precede translation of its message.
 ...
PMID:Expression of myosin heavy chains during thyroid hormone-induced cardiac growth. 375 76

The expression of mRNAs for two cardiac myosins has been examined in the ventricles of hypo- and hyperthyroid rabbits by means of cloned cDNA sequences corresponding to the mRNAs of the alpha- and beta-myosin heavy chains (HCs). The temporal change in the relative levels of the alpha- and beta-HC mRNAs after 3,5,3'-triiodothyronine (T3) treatment of hypothyroid rabbits was determined by nuclease S1 mapping. In the hypothyroid state, only HC beta-mRNA was expressed in the ventricles. The HC alpha-mRNA was first detectable 4 h after administration of T3 (200 micrograms/kg) to hypothyroid animals. By 12 h, HC alpha-mRNA represented 20% of total myosin mRNA, increasing to 50% by 24 h and to about 90% by 72 h. The relationship between the relative mRNA levels and relative synthesis rates of the myosin HCs was evaluated in 5-6-week-old normal and thyrotoxic rabbits. Myosin synthesis rates were determined by labeling of protein in vivo with [3H]leucine. The V1 (HC alpha) and V3 (HC beta) isomyosins were separated by affinity chromatography with monoclonal antibodies, and the HCs were isolated electrophoretically. In a normal euthyroid group of animals and in animals 12 and 24 h after administration of 200 micrograms of 3,5,3',5'-tetraiodothyronine/kg, the relative mRNA levels and relative synthesis rates of the alpha- and beta-HCs were not significantly different. Our results show that, first, thyroid hormone causes a rapid accumulation of HC alpha-mRNA and loss of HC beta-mRNA and, second, in normal and thyrotoxic rabbits, the relative synthesis rates of HC alpha and HC beta reflect the relative abundance of the alpha- and beta-HC mRNAs.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Regulation of myosin synthesis by thyroid hormone: relative change in the alpha- and beta-myosin heavy chain mRNA levels in rabbit heart. 632 4