鳜鱼胰蛋白酶和淀粉酶与胃蛋白酶原基因的克隆与序列分析

采用RT-PCR及RACE法,克隆得到鳜鱼(Siniperca chuatsi)肝胰脏胰蛋白酶(trypsin, Try)、淀粉酶(amylase, Amy)基因 cDNA全序列.结果表明,鳜鱼Try基因cDNA全长为896 bp,其中开放阅读框 (open reading frame,ORF)为744 bp,编码247个氨基酸. 序列同源性分析发现,鳜鱼Try与 斑马鱼(Danio rerio)、非洲爪蟾(Xenopus laevis)、 小鼠Try和人TRY氨基酸序列同源性分别为81.4%、75.3%、74.5%和71.4%.鳜鱼Amy 基因cDNA全长为1 647 bp,其中ORF为1 539 bp,编码512个氨基酸.鳜鱼Amy与斑马鱼 、非洲爪蟾、小鼠Amy和人AMY氨基酸序列同源性分别为79.7%、75.4%、71.9%和70.9%. 同时对鳜鱼基因组进行PCR,获得鳜鱼Try、Amy与胃蛋白酶原(pepsinogen, Pep)全基因组DNA序列.序列分析表明,鳜鱼Try基因由4个内含子和5个外显子组成,全长1 362 bp;鳜鱼Amy基因由8个内含子和9个外显子组成,全长4 267 bp;鳜鱼Pep基因由8个内含子和9个外显子组成,全长 4 032 bp,与其它脊椎动物基因结构相似.应用Genome walker方法在鳜鱼克隆得到长度分别为1 189 bp、413 bp和527 bp的Try、Amy和Pep基因的5′侧翼区序列以及1段长为704 bp的Pep 基因3′侧翼区序列,并利用相关软件预测其中具有多个可调节其表达的调控元件.鳜鱼Try、Am y和Pep基因组全序列的克隆及其序列、结构分析和分子系统进化等的研究,为鱼类消化代谢相关基因的生理功能及表达调控机理进一步研究提供依据.     

The C1orf9 gene encodes a putative transmembrane member of a novel protein family

Here we report the characterization of a human mRNA encoding a novel protein denoted C1orf9 (chromosome 1 open reading frame 9). The cDNA sequence, derived from a testis cDNA library, contains 5700 bp which encodes an open reading frame of 1254 amino acids. The deduced protein contains a putative N-terminal signal peptide and one putative transmembrane region, indicating membrane localization. No significant homology was found with known characterized proteins. However, a 150 amino acid region has significant homology to deduced protein sequences from other organisms, including Caenorhabditis elegans (43% identity), Saccharomyces cerevisiae (47% identity), Schizosaccharomyces pombe (48% identity), and two proteins from Arabidopsis thaliana (42% and 40% identity), suggesting a novel family of conserved domains. The C1orf9 gene was assigned to chromosome 1q24. The gene spans approximately 78.7 kb and is organized into at least 24 exons. Expression analysis revealed a single C1orf9 mRNA species of approximately 6.0 kb with a predominant expression in pancreas and testis, and only low levels of expression in other tissues examined.     

Structure of the human hepatic triglyceride lipase gene

The structure of the human hepatic triglyceride lipase gene was determined from multiple cosmid clones. All the exons, exon-intron junctions, and 845 bp of the 5' and 254 bp of the 3' flanking DNA were sequenced. Comparison of the exon sequences to three previously published cDNA sequences revealed differences in the sequence of the codons for residues 133, 193, 202, and 234 that may represent sequence polymorphisms. By primer extension, hepatic lipase mRNA initiates at an adenine 77 bases upstream of the translation initiation site. The hepatic lipase gene spans over 60 kb containing 9 exons and 8 introns, the latter being all located within the region encoding the mature protein. The exons are all of average size (118-234 bp). Exon 1 encodes the signal peptide, exon 4, a region that binds to the lipoprotein substrate, and exon 5, an evolutionarily highly conserved region of potential catalytic function, and exons 6 and 9 encode sequences rich in basic amino acids thought to be important in anchoring the enzyme to the endothelial surface by interacting with acidic domains of the surface glycosaminoglycans. The human lipoprotein lipase gene has been recently reported to have an identical exon-intron organization containing the analogous structural domains [Deeb & Peng (1989) Biochemistry 28, 4131-4135]. Our observations strongly support the common evolutionary origin of these two lipolytic enzymes.     

Genome-type-specific variation of the 19th intron sequence within the RNA polymerase I largest subunit gene in the genus Oryza

Rice PolA1 gene, encoding for the largest subunit of RNA polymerase I, spans ca. 15 kb containing 21 exons and presents as a single-copy-per-haploid genome. The genus Oryza comprises 22 wild species and 9 recognized genome types: AA, BB, CC, EE, FF, GG, BBCC, CCDD, and HHJJ. We analyzed sequences of the 19th intron (PI19) within PolA1 genes in 17 Oryza species. The AA species, containing two cultivated species, showed similar length of PI19 to that of CC species (287–296 bp). The longer PI19s were found in BB (502 bp) and FF (349 bp) species, although EE (217 bp) and GG (222 bp) species had shorter sequences. The size differences of the PI19s are particularly useful to discriminate between diploid (BB and CC) and allotetraploid (BBCC) species using simple PCR analysis. The evolutionary relationship among seven genomes was inferred based on the comparison of their PI19 sequences.     

The rat peptidylarginine deiminase-encoding gene: structural analysis and the 5'-flanking sequence.

Genomic clones of the rat peptidylarginine deiminase (PAD)-encoding gene (PAD) were isolated, and the gene organization was analyzed by restriction mapping and nucleotide sequencing. The PAD spans more than 50 kb and contains 16 exons and 15 introns. The lengths of the introns from 0.5 kb to more than 16.5 kb. A 1.7-kb sequence in the 5'-flanking region was determined. S1 nuclease mapping revealed two putative cap sites 79 and 81 bp upstream from the N-terminal ATG codon of PAD, which had been determined by amino acid sequence analysis. This ATG was confirmed to be the translation start site, since no other ATG codon was found in the open reading frame downstream from the cap sites. The 5'-flanking sequence contains four potential SP1-binding sites, a putative Pit-1/GHF-1-binding site, four short sequences either identical or homologous to the sequences in the promoter regions of rat or human growth hormone encoding genes, as well as a sequence similar to an estrogen-responsive element. However, neither a typical TATAA box, nor CCAAT box is present. These results provide important clues for elucidating the mechanism of female-specific and/or sex cycle-dependent gene expression.     

Characterization of the porcine FSCN3 gene: cDNA cloning, genomic structure, mapping and polymorphisms

Fascin 3 (FSCN3)is a testis-specific actin-bundling protein involved in spermatid development. Here we describe the molecular characterisation of the porcine FSCN3 gene. The 1,800-bp cDNA sequence contains a 1,497-bp open reading frame encoding a protein of 498 amino acids with a calculated molecular mass of 56.2 kDa and an isoelectric point of 6.82. The porcine FSCN3 protein shares high identity with other mammalian FSCN3. The FSCN3 gene contains seven exons, spans approximately 9 kb, and maps to pig chromosome 18. We also identified 24 DNA polymorphisms.