5-Noncoding sequences have been tabulated for 211 messenger RNAs from higher eukaryotic cells. The 5'-proximal AUG triplet serves as the initiator codon in 95% of the mRNAs examined. The most conspicuous conserved feature is the presence of a purine (most often A) three nucleotides upstream from the AUG initiator codon; only 6 of the mRNAs in the survey have a pyrimidine in that position. There is a predominance of C in positions -1, -2, -4 and -5, just upstream from the initiator codon. The sequence CCAGCCAUG (G) thus emerges as a consensus sequence for eukaryotic initiation sites. The extent to which the ribosome binding site in a given mRNA matches the -1 to -5 consensus sequence varies: more than half of the mRNAs in the tabulation have 3 or 4 nucleotides in common with the CCACC consensus, but only ten mRNAs conform perfectly.

Compilation and analysis of sequences upstream from the translational start site in eukaryotic mRNAs

http://theory.bio.uu.nl/immbio/Marks91.pdf

By-passing immunization: Human antibodies from V-gene libraries displayed on phage

A procedure is described for the large-scale purification of light (L) and heavy (H) chain mRNAs from plasmacytomas produced in mice. Intact RNA is selectively precipitated in high yield from frozen tumors homogenized in 3 M LiCl and 6 M urea. L and H-chain mRNAs were purified by oligo(dT)-cellulose chromatography and either sucrose gradient centrifugation in conditions preventing aggregation or by means of high-resolution preparative gel electrophoresis under non-denaturing conditions. γ2a and α H-chain mRNAs sedimented as major components at 15.5 S and 16.5 S respectively, when L-chain mRNAs sedimented as 12-S species. H-chain mRNAs isolated by continuous elution during preparative gel electrophoresis were completely separated from both L-chain mRNA and residual 18-S rRNA, and migrated as single components of 1900 ± 50 nucleotides on analytical denaturing gels. The partially purified H-chain mRNAs were translated into major components of molecular weights of 56000 (γ2a) and 60000 (α) in an mRNA-dependent rabbit reticulocyte lysate, whereas L-chain mRNAs yielded polypeptides of molecular weights of 25000 (λ) and 27000 (к). Up to 95% of the translation products directed by the purified mRNAs were immunoprecipitated using specific antisera. The purity of L and H-chain mRNAs was assessed by hybridization of corresponding cDNAs with excess recombinant plasmid DNA. The results indicated a minimum purity of 47% (γ2a), 62% (α), for H-chain mRNAs and 60% (к), for L-chain mRNAs.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1980.tb06030.x

Purification of mouse immunoglobulin heavy-chain messenger RNAs from total myeloma tumor RNA.

ALKBH5 Is a Mammalian RNA Demethylase that Impacts RNA Metabolism and Mouse Fertility

A 3'-end proximal segment of most of the putative mRNAs encoded in the heavy strand of HeLa cell mtDNA has been partially sequences and aligned with the DNA sequence. In all cases, the 3'-end nucleotide of the individual mRNA coding sequences has been found to be immediately contiguous to a tRNA gene or another mRNA coding sequence. These and previous results indicate that the heavy (H) strand sequences coding for the rRNA, poly(A)-containing RNA and tRNA species form a continuum extending over almost the entire length of this strand. We propose that the H strand is transcribed into a single polycistronic RNA molecule, which is processed later into mature species by precise endonucleolytic cleavages which occur, in most cases, immediately before and after a tRNA sequence.

U. Schibler

Papers

Tissue-specific in vitro transcription from the mouse albumin promoter

Two promoters of different strengths control the transcription of the mouse alpha-amylase gene Amy-1a in the parotid gland and the liver

The synthesis and processing of the messenger RNAs specifying heavy and light chain immunoglobulins in MPC-11 cells.

Comparison of methylated sequences in messenger RNA and heterogeneous nuclear RNA from mouse L cells.

Tissue-specific expression of mouse alpha-amylase genes.