MRNA cycling

Rutila JE, Suri V, Le M, So WV, Rosbash M, Hall JC 1998 CYCLE is a second bHLH-PAS protein essential for circadian transcription of Drosophila period and timeless. Cell 93 805-814 So WV, Rosbash M 1997 Post-transcriptional regulation contributes to Drosophila clock gene mRNA cycling. EMBO J 16 7146-7155... 

Zehring WA, Wheeler DA, Reddy P et al 1984 P-element transformation withperiod oca.% DNA restores rhythmicity to mutant, arrhythmic Drosophila melanogaster. Cell 39 369-376 Zeng H, Hardin PE, Rosbash M 1994 Constitutive overexpression of the Drosophila period protein inhibits period mRNA cycling. EMBO J 13 3590-3598... 

Mahmood R, Mittra B, Hines JC et al. Characterization of the Crithidia fasciculata mRNA cycling sequence binding proteins. Mol Cell Biol 2001 21(14) 4453-9. 

The now deacylated tRNA is attached by its anticodon to the P site at one end and by the open GGA tail to an exit (E) site on the large ribosomal subunit (Figure 38-8). At this point, elongation factor 2 (EE2) binds to and displaces the peptidyl tRNA from the A site to the P site. In turn, the deacylated tRNA is on the E site, from which it leaves the ribosome. The EF2-GTP complex is hydrolyzed to EF2-GDP, effectively moving the mRNA forward by one codon and leaving the A site open for occupancy by another ternary complex of amino acid tRNA-EFlA-GTP and another cycle of elongation. 

The levels of MAPK mRNA do not appear to change during the cell cycle instead, regulation of MAPK activity occurs post-translationally,... 

Our studies of the ERT cell cycles show that they are regulated by nutrition (Britton Edgar 1998). If the newly hatched larva is starved for dietary amino acids, DNA replication in most ERTs is not initiated. Under starvation conditions these tissues express low levels of cyclin E and E2F, the transcription factor which is probably responsible for cyclin E expression. If either E2F or cyclin E is induced in starved larvae, DNA replication in the ERTs is activated, and thus expression of these genes appears to limit the ERT cell cycle. When nutrient-deprived larvae are fed, expression of E2F and cyclin E mRNAs increases approximately sixfold, and DNA replication is initiated in most ERT cells. If the animal is first fed and then starved, the ERT cell cycle is activated and then inactivated quite rapidly. These experiments all indicate that the ERT cell cycle is nutrition-responsive, rather than controlled by a rigid developmental program. 

Thompson, A. J., A. C. Jackson et al. (2000a). Abscisic acid biosynthesis in tomato Regulation of zeaxanthin epoxidase and 9-cw-epoxycarotenoid dioxygenase mRNAs by light/dark cycles, water stress and abscisic acid. Plant Mol. Biol. 42(6) 833-845. 

Several studies suggest that cortistatin expression correlates with the sleep homeostat. The concentration of cortistatin mRNA oscillates with the light-dark cycle in rats, with maximal levels at the end of the dark (i.e. active) period. Further, the steady-state concentration of cortistatin mRNA increases four-fold after sleep deprivation, and returns to normal levels after sleep rebound, indicating that the expression of the peptide is associated with sleep demand (Spier de Lecea, 2000). Preliminary studies in cortical slices suggest that cortistatin-14 increases cortical synchronization by enhancing the H-current. Thus, cortistatin and somatostatin may be part of the intrinsic mechanisms of the cerebral cortex that are involved in the maintenance of excitability. 

Friedman et al. (2000) tested this approach on a data set for yeast cell cycle expression patterns provided by Spellman and co-workers (1998), writing that This data set contains 76 gene expression measurements of the mRNA levels of 6177 S. cerevisiae ORFs. These experiments measure six... 

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