Messenger ribonucleic acid of the lipoprotein of the Escherichia coli outer membrane. II. The complete nucleotide sequence

The complete nucleotide sequence of the mRNA for the outer membrane lipoprotein from Escherichia coli has been determined. All the ribonuclease T1 and ribonuclease A fragments obtained from the mRNA were connected with DNA sequencing of restriction endonuclease fragments of the cloned lipoprotein gene. The mRNA consists of 322 nucleotides, and there are 38 and 50 nucleotides in the 5' and 3' end untranslated regions, respectively. The mRNA has several unique features: (a) Out of 50 possible codons for 15 amino acids in the prolipoprotein only 25 codons are used, and all of these appear to be read by the major isoaccepting species of tRNAs for individual amino acids. (b) In the first 64 nucleotides from the 5' end, there are no obvious secondary structures. On the other hand, between the 65th nucleotide and the 3' end, 85% of the nucleotides are involved in the formation of secondary structures, with nine stable stem-and-loop structures. (c) There are many repeating sequences including one repeat of 40 nucleotides. (d) There are a few other features which could be important for efficient translation of the mRNA.     

Translation is required for regulation of histone mRNA degradation

When DNA synthesis is inhibited, the mRNAs coding for the replication-dependent histone proteins are selectively destabilized. The histone genes have been altered and reintroduced into tk- mouse L cells by cotransfection with the herpesvirus thymidine kinase gene. Two features of the mRNA are necessary for regulation of degradation: first, the hairpin loop must be present at the 3' end of the histone mRNA; and second, the histone mRNA must be capable of being translated to within 300 nucleotides of the 3' end of the RNA. Polyadenylated histone mRNAs are stable, as are histone mRNAs that contain in-frame termination codons early in the coding region or 500 nucleotide 3' untranslated regions with a normal hairpin loop at the 3' end.     

Skeletal muscle actin mRNA. Characterization of the 3' untranslated region.

Plasmids p749, p106, and p150 contain cDNA inserts complementary to rat skeletal muscle actin mRNA. Nucleotide sequence analysis indicates the following sequence relationships: p749 specifies codons 171 to 360; p150 specifies codons 357 to 374 together with 120 nucleotides of the 3'-non-translated region; p106 specifies the last actin amino acid codon, the termination codon and the entire 3' non-translated region. Plasmid p749 hybridized with RNA extracted from rat skeletal muscle, cardiac muscle, smooth (stomach) muscle, and from brain. It also hybridizes well with RNA extracted from skeletal muscle and brain of dog and chick. Plasmid p106 hybridized specifically with rat striated muscles (skeletal and cardiac muscle) mRNA but not with mRNA from rat stomach and from rat brain. It also hybridized to RNA extracted from skeletal muscle of rabbit and dog but not from chick. Thermal stability of the hybrids and sensitivity to S1 digestion also indicated substantial divergence between the 3' untranslated end of rat and dog skeletal muscle actins. The investigation shows that the coding regions of actin genes are highly conserved, whereas the 3' non-coding regions diverged considerably during evolution. Probes constructed from the 3' non-coding regions of actin mRNAs can be used to identify the various actin mRNA and actin genes.     

The sequence of a cloned cDNA for the beta subunit of bovine thyrotropin predicts a protein containing both NH2-and COOH-terminal extensions

Cloned cDNAs containing sequences coding for the beta subunit of bovine thyrotropin have been identified. The complete nucleotide sequence of the largest of the beta subunit cDNA inserts has been determined. This cDNA contains 35 nucleotides from the 5' untranslated region of thyrotropin beta subunit mRNA and 60 nucleotides coding for an NH2-terminal precursor segment. This is followed by 339 nucleotides which code for the published amino acid sequence of the thyrotropin beta subunit. Following the 339 nucleotide beta subunit coding sequence, no termination codon is encountered for another 15 nucleotides. Thus, the cDNA codes for a thyrotropin beta subunit containing an additional 5 amino acids at the COOH terminus. The cDNA also contains 82 nucleotides of 3' untranslated sequence followed by a short poly(A) segment. Comparison of the bovine cDNA sequence to the recently described mouse thyrotropin beta subunit cDNA sequence reveals considerable homology throughout the coding sequence, including the COOH-terminal extension. These findings suggest the possibility that a thyrotropin beta subunit precursor is processed at both the NH2 and COOH termini.     

A mouse immunoglobulin heavy chain deletion mutant: isolation of a cDNA clone and sequence analysis of the mRNA

The mouse cell line IF2 secretes an immunoglobulin heavy chain lacking the CH1 domain. We have isolated and characterised a recombinant plasmid containing cDNA copies of the IF2 mutant mRNA. The cloned sequence extends from the nucleotides coding for amino acid 96 in the variable region through 100 nucleotides of untranslated region at the 3' end. The sequence of the cDNA insert reveals no discontinuity at the variable-hinge region junction, the site of the CH1 deletion. Experiments employing direct priming on the poly(A) tail of the IF2 heavy chain mRNA suggest that the 3' end of the cDNA clone (sequence C-C-C-T-G-C) is also the 3' end of the mRNA.     

Structure of the constant and 3' untranslated regions of the murine Balb/c gamma 2a heavy chain messenger RNA.

The complete sequence for the constant and 3' untranslated regions of a mouse gamma 2a immunoglobulin heavy chain mRNA is reported. The sequence is 1093 nucleotides long coding for the CH1 (amino-acids 118-214), the Hinge (215-230), the CH2 (231-340) and the CH3 (341-447). The 3' untranslated region is 103 nucleotides long preceding the poly(A). The nucleotide sequence predicts as in the case for gamma 1 and gamma 2b heavy chains an additional lysine residue before the termination codon. This sequence has been compared to the corresponding sequences of gamma 1 and gamma 2b heavy chain mRNAs. These sequences are respectively 75% and 84% homologous. The CH2 domains of gamma 2a and gamma 2b are 95% homologous at the nucleotide level. The cross-over point of a gamma 2a - gamma 2b heavy chain variant is located in a segment of 73 perfectly matching nucleotides. The 3' non coding regions of gamma 2a and gamma 2b are 89% homologous.     

Molecular cloning and nucleotide sequencing of human immunoglobulin epsilon chain cDNA.

DNA complementary to mRNA of human immunoglobulin E heavy chain (epsilon chain) isolated and purified from U266 cells has been synthesized and inserted into the PstI site of pBR322 by G-C tailing. This recombinant plasmid was used to transform E. coli chi 1776 to screen 1445 tetracycline resistant colonies. Nine clones (pGETI - 9) containing cDNA coding for the human epsilon chain were recognized by colony hybridization and Southern blotting analysis with a nick-translated human IgE genome fragment. The nucleotide sequence of the longest cDNA contained in pGET2 was determined. The results indicate that the sequence of 1657 nucleotides codes for 494 amino acids covering a part of the variable region and all of the constant region of the human epsilon chain. Most of the amino acid sequence deduced from the nucleotide sequence is in substantial agreement with that reported. Furthermore a termination codon after the -COOH terminal amino acid marks the beginning of a 3' untranslated region of 125 nucleotides with a poly A tail. Taking this into account, the structure of the human epsilon chain mRNA, except a part of the 5' end, is conserved fairly well in the cDNA insert in pGET2.     

稻瘟病菌(Magnaporthe grisea)诱导的水稻早期反应基因ER1的5' 端cDNA片段克隆及序列分析

研究高等生物基因表达与调控的一个重要方面是分离基因的编码区及其上游的调控序列（ＤｅＶｅｅｒ等１９９７）,这需要获得一个基因的ｃＤＮＡ全长及从植物基因组获取全基因。在前文（周建明等１９９９）中曾经分离了稻瘟病菌侵染诱导的水稻早期反应基因ＥＲ１的ｃＤＮＡ片段,但是运用ｍＲＮＡ差异显示技术分离的ｃＤＮＡ片段往往只有近ｍＲＮＡ３’端的一部分,难以反映基因的结构及功能特点,因此,必须进一步分离其５’端的部分才有可能比较全面地了解此基因的特点。ＲＡＣＥ（ｒａｐｉｄａｍｐｌｉｆｉｃａｔｉｏｎｏｆｃＤＮＡｅｎ…