Isolation and characterization of the rat proenkephalin gene

The rat proenkephalin gene has been isolated by molecular cloning and characterized by DNA-sequence analysis. The gene exhibits a structural organization similar to that of the human gene. The nucleotide sequence encoding the biologically active opioid peptides which are generated from the proenkephalin precursor as well as the 3' untranslated region of the mRNA are found on a large exon at the 3' end of the gene (Exon III). The nucleotide sequence encoding the N terminus of the mature protein and its signal peptide are located on Exon II while Exon I encodes the 5' untranslated region of the mRNA. The nucleotide sequence of these exons and their flanking regions has been determined and compared to the human proenkephalin gene. Analysis of the nucleotide sequence homology between the human and rat proenkephalin gene reveals the presence of highly conserved regions within both the coding and noncoding portions of the genes. Enkephalin-coding sequences as well as 5' flanking sequences appear to be the most highly conserved. The importance and possible function of these sequences are discussed.     

Partial characterization of bovine elastin gene; comparison with the gene for human elastin

A 14 kilobase (kb) genomic clone of the gene for bovine elastin, containing exons 1 and 2, has been characterized. This clone extends about 6.5 kb in the 5' direction from the initiation codon and 978 nucleotides in the 3' direction from exon 2. The size of the first intron is about 6.4 kb. The sequence immediately 5' to the initiation codon is highly conserved between the genes for bovine and human elastins and contains a TATA box consensus sequence (ATAAA), CAAT, and Sp1 binding sites. Several putative AP-2 binding sites are also present. Comparative analysis of the sequences flanking the first exon in the genes for bovine and human elastins identified conserved sequences that may be regulatory control elements. A putative enhancer core sequence is present in the first intron of the genes for bovine and human elastins.     

Evolution of the casein multigene family: conserved sequences in the 5'' flanking and exon regions.

The rat alpha- and bovine alpha s1-casein genes have been isolated and their 5' sequences determined. The rat alpha-, beta-, gamma- and bovine alpha s1-casein genes contain similar 5' exon arrangements in which the 5' noncoding, signal peptide and casein kinase phosphorylation sequences are each encoded by separate exons. These findings support the hypothesis that during evolution, the family of casein genes arose by a process involving exon recruitment followed by intragenic and intergenic duplication of a primordial gene. Several highly conserved regions in the first 200 base pairs of the 5' flanking DNA have been identified. Additional sequence homology extending up to 550 base pairs upstream of the CAP site has been found between the rat alpha- and bovine alpha s1-casein sequences. Unexpectedly, the 5' flanking promoter regions are conserved to a greater extent than both the entire mature coding and intron regions of these genes. These conserved 5' flanking sequences may contain potential cis regulatory elements which are responsible for the coordinate expression of the functionally-related casein genes during mammary gland development.     

Chromosomal arrangement of the duck alpha-globin genes and primary structure of the embryonic alpha-globin gene pi

A recombinant lambda Charon 4A bacteriophage, D alpha G-1, carrying the genes coding for the duck embryonic (pi') and adult (alpha A, alpha D) alpha-like globins was isolated from a previously constructed duck DNA recombinant library. The three globin genes are transcribed from the same DNA strand and are arranged in the order of their expression during development: 5'-pi'-alpha D-alpha A-3'. We have determined the complete nucleotide sequence of the duck pi'-globin gene, including the flanking regions. Due to the unusual length of intron 1 (963 bp) and intron 2 (568 bp) the 2167-bp duck pi'-globin gene is by far the largest among all known mammalian or avian alpha- and beta-globin genes. For instance, the duck pi'-globin gene introns are almost twice as long as those of the chicken pi'-globin genes. A surprisingly high degree of nucleotide sequence homology (88%) has been found for the 5' flanking region (positions -1 to -223) of the duck and chicken pi'-globin gene.     

人淋巴细胞CD2基因5’侧翼序列的克隆和鉴定

本文报告以ＣＤ２ｃＤＮＡ５’端的片段作探针,从人Ｔ淋巴细胞基因组文库筛选阳性重组克隆,经限制性内切酶降解和Ｓｏｕｔｈｅｒｎ杂交分析,证明其中一个阳性克隆的插入片段中含ＣＤ２基因５’侧翼顺序。经插入片段的亚克隆、限制性内切酶图谱及ＤＮＡ序列分析,鉴定出一含转录起始点及其上游序列的４．０ｋｂ片段。将此片段中含转录起始点和两个ＤＮ（ａｓｅ）Ⅰ高敏感位点的２．５ｋｂ片段定向克隆到以虫萤光素酶为报告基因的表达载体ｐＭＧ３中,并用限制性内切酶对此２．５ｋｂ片段作不同程度缺失,构成一系列突变子。这些重组的表达质粒转染人ＪｕｒｋａｔＴ细胞后,以瞬时表达实验分析各突变子驱动虫萤光素酶基因的表达,结果发现在ＣＤ２基因５’上游具有很弱的启动子活性,初步测定该启动子位于－１．２ｋｂ～－９８ｂｐ域。ＣＤ２基因具有弱启动子、强增强子的特点与Ｔ细胞表面其它抗原分子基因是相似的。     

Structural analysis of the regulatory region of the human corticotropin releasing hormone gene

A DNA fragment containing the human corticotropin releasing hormone (CRH) gene, along with 9 kb of upstream and 4 kb of downstream sequences, was isolated from a human genomic DNA library. Nucleotide sequence analysis of the proximal 918 nucleotides 5' flanking the putative major mRNA start site of the human gene and comparison to the 866 nucleotide long homologous ovine sequence, revealed that this region of the CRH gene consists of two distinct areas with different degrees of homology, varying from 72% to 94%. The putative functional features of the human sequence were identified. Many, but not all, features were conserved in the ovine sequence. The highly conserved nature of the regulatory region of this gene makes it a good candidate for tracing possible related genetic defects of the hypothalamic-pituitary-adrenal (HPA) axis.