摘要:

We have investigated the actin-related sequences in soybean using heterologous actin DNA probes fromDictyostelium, Drosophila, and yeast. Southern blot analysis of restriction digests of soybean DNA indicates that actin is encoded in a small multigene family. In order to isolate individual members of this gene family, we have constructed a soybean genomic library in the λ vehicle Charon 4A. A partial characterization of this library shows it to be nearly complete. We have isolated from this library a number of recombinant clones that hybridize to actin-coding sequences from all three heterologous probes. We have identified the fragments containing the actin-related sequences on the physical maps of two of these clones λSAcl and λSAc3. These fragments were subcloned in the plasmid vehicle pBR322. Using electron microscope heteroduplex mapping we show that the subclones, pSAc1 and pSAc3, share homology with the entire actin-coding sequence (1.1 kb) ofDrosophilaandDictyostelium. Furthermore, pSAc1 and pSAc3 have additional homology of approximately 0.22 kb at the 5′ ends of their coding sequences. No homology is detected in the 3′ flanking regions of these clones. The actin sequence in pSAc1 contains an interruption of approximately 0.30 kb located 0.39 kb from the 5′ end of the actin polypeptide codin

ISSN:1044-5498    

DOI:10.1089/dna.1.1981.1.1

年代:1981

数据来源: MAL

摘要:

We report the nucleotide sequence of a gene encoding the constant region of a human immunoglobulin γ4 heavy chain (Cγ4). These data represent the first complete sequence determination of a human CHgene. As expected from structural studies of mouse Cγgenes, the coding sequences for the CHdomains and hinge segment are separated from one another by intervening DNA sequences. Comparison with genomic sequences of the mouse Cγ1, Cγ2a, and Cγ2bgenes shows conservation of the sequences in the constant region domains and the 3′ untranslated region surrounding the presumed site of poly(A) a

ISSN:1044-5498    

DOI:10.1089/dna.1.1981.1.11

年代:1981

数据来源: MAL

摘要:

Uteroglobin is a protein that is synthesized in large quantities by the rabbit uterine endometrial cells and secreted into the uterine lumen around the time of implantation of the developing blastocysts. The protein is also synthesized constitutively at a low level in the lung. In the uterus, synthesis of the protein is induced by progesterone but repressed by estradiol; whereas in the lung, it is not hormonally responsive. Using a full-length cDNA clone, we have established the nucleotide sequence of uteroglobin mRNA and have determined its levels in uterus and lung during early pregnancy. The clone, pUG617, contains all but 24 nucleotides at the 5′ untranslated region of the structural gene. To establish the full mRNA sequence, we isolated a 5′ endlabeled DNA fragment from pUG6T7 and extended its length using reverse transcriptase after hybridization with uterine poly(A)-containing RNA. The 5′-terminal sequence of uteroglobin mRNA was established by sequencing the extended DNA fragment. The nucleotide sequence of the peptide-coding portion of the gene has resolved some previously reported discrepancies in the amino acid sequence of the mature protein and those in the signal peptide. By comparison of sequences with a partial uteroglobin cDNA clone isolated by another laboratory, a polymorphic nucleotide at position 246 of the gene has been identified, where a G-A transition has caused an amino acid substitution from aspartic acid to asparagine at residue 46 of the mature protein. Analysis of steady-state RNA levels in the uterus has shown that the induction and repression of uteroglobin synthesis during early pregnancy is the result of accumulation and depletion of its mRNA, respectively. During the same period in the lung, no consistent changes in uteroglobin mRNA level were evident, reflecting the constitutive levels of the protein in this t

ISSN:1044-5498    

DOI:10.1089/dna.1.1981.1.19

年代:1981

数据来源: MAL

摘要:

We have constructed several cloning vectors which can be used inin vitropackaging and yeast transformation. These plasmids have been designed for the convenient cloning of large segments of DNA and their transfer to yeast. They contain bacterial plasmid DNA sequences for replication and selection inEscherichia coli, yeast 2-μm plasmid DNA sequences or chromosomal replicators and yeast markers necessary for replication and selection in yeast, and the cohesive ends of bacteriophage λ which allow packaging of recombinant molecules into λ phage heads. Large fragments (22-38 kb) ofKlebsiella pneumoniaeandZea maysDNA were ligated into plasmid vector pBTI-1 to make complete genome libraries. One clone from theK. pneumoniaelibrary was amplified inE. coliand the purified DNA used to transform yeast cells. Transformation of yeast by large DNA fragments occurred at high frequencies. The recombinant plasmid was stably maintained in yeast, provided selective pressure for Leu+transformants was maintained. The structurally complete recombinant plasmid can be recovered from yeast by transformingE. colito ampicillin resistance. Fewer than 5% of the recovered plasmids had undergone recombination with endogenous yeast 2-μm plas

ISSN:1044-5498    

DOI:10.1089/dna.1.1981.1.27

年代:1981

数据来源: MAL

摘要:

Prolactin, growth hormone, and chorionic somatomammotropin (placental lactogen) constitute a set of related polypeptides believed to derive from a common evolutionary ancestor protein. We have cloned and sequenced DNA complementary to the mRNA coding for bovine prolactin. This cDNA contains 702 bases corresponding to 10 amino acids in the leader peptide, all 199 amino acids of the hormone, and 75 nucleotides in the 3′ untranslated region of the mRNA. Nucleotide sequence analysis of this cDNA permitted the identification of 10 amino acids in the signal peptide, plus the correction or elucidation of amino acid assignments at 16 sites where aspartic and glutamic acids had not been distinguished from their amides by amino acid sequencing. Codon usage in bovine prolactin mRNA is nonrandom, but, similarly to rat and human prolactins, it does not exhibit the strong preference for G or C in codon third positions seen in bovine, rat, and human growth hormone mRNAs. The translational termination signal in bovine prolactin in UAA, also the same as in rat and human prolactins and differing from the UAG "stop" codon used in bovine, rat, and human growth hormones and human chorionic somatomammotropin. The amino acid and mRNA nucleotide sequences of bovine, rat, and human prolactins and growth hormones were compared by several techniques based on various theories of molecular evolution. The comparison of prolactin to growth hormone is consistent in all three species, suggesting that the genes for these two hormones diverged about 350 million years ago. However, comparisons among the three prolactins or among the three growth hormones to determine the times of evolutionary divergence of the three species generated values that were inconsistent with each other and with the fossil record. Analysis of these discrepancies suggests that the genes for prolactin and growth hormone may now be evolving by different mechanism

ISSN:1044-5498    

DOI:10.1089/dna.1.1981.1.37

年代:1981

数据来源: MAL

ISSN:1044-5498    

DOI:10.1089/dna.1.1981.1.51

年代:1981

数据来源: MAL

摘要:

We report the first isolation and identification of a mouse genomic fragment encoding amino acid sequences for the proα1(I) chain of type I procollagen. The DNA sequence of eight coding sequences is presented; five of these are 54 bp and three are 108 bp in length. Together these specify 198 amino acids which are 94% homologous to the corresponding bovine proα1(I) chain protein sequences. Each of the eight coding sequences is flanked by appropriate splice-junction sequences that exhibit considerable sequence complementarity to the rat small nuclear U1a RNA. In the 198 codons examined in this mouse genomic clone, the preferred codons for glycine and alanine are GGU (46/67) and GCU (23/30), respectively. This is in contrast to the codon usage reported for the chicken proα1(I) cDNA clone (Fuller and Boedtker, 1981). The examined coding sequences exhibit considerable nucleotide homology in both end-to-end and in staggered alignments. Based on an analysis of this homology data, a model is presented for the generation of 108-bp coding sequences from 54-bp units by two successive homologous recombinational events within coding sequences. Alternatively, the 108-bp units may have arisen by precise deletions of an intervening sequence between 54-bp coding sequences. Evidence supporting this is provided by a comparison of proα1(I) and proα2(I) genes. In the mouse proα1(I) gene amino acids 856-891 are encoded in a 108-bp unit; in the chicken proα2(I) gene these residues are encoded in two 54-bp coding sequences. In addition, the coding sequences for nearly 50% of the α domain are condensed in the proα1(I) gene into a region approximately one half the size occupied by the comparable sequences in the proα

ISSN:1044-5498    

DOI:10.1089/dna.1.1981.1.59

年代:1981

数据来源: MAL

ISSN:1044-5498    

DOI:10.1089/dna.1.1981.1.71

年代:1981

数据来源: MAL

ISSN:1044-5498    

DOI:10.1089/dna.1.1981.1.79

年代:1981

数据来源: MAL