[Construction and expression of recombinant human serum albumin-EPO fusion protein].

UNLABELLED: OBJECTIVE To construct the recombinant plasmid pCI-HLE encoding human serum album-EPO (HSA-EPO) fusion protein and to express it in CHO cell. METHODS: The cDNA encoding human serum album and EPO were amplified by PCR, and then spliced with the synsitic DNA fragment encoding GS (GGGGS), by overlap PCR extension to form LEPO. After BamH I digestion, the HSA and LEPO was ligated to generate the fusion HSA-EPO gene and was then cloned into the expression vector pCI-neo to generate the recombinant plasmid pCI-HLE. The plasmid pCI-HLE was transfected into CHO cell by liposome protocol. Then, the recombinant cells were screened by G418 and identified by PCR and Western blot. Expression of fusion protein was evaluated by Enzyme Linked Immunosorbent Assay (ELISA). RESULTS: Restrictive enzymes digestion and DNA sequencing revealed that HSA-EPO fusion gene was cloned into expression vector pCI-neo successfully. PCR and Western blot analysis confirmed that the fusion gene was integrated in the genome of CHO cells and expressed successfully. The HSA-EPO production varied from 86 Iu/(mL x 10(6) x 72 h) to 637 IU/(mLx 10(6) x 72 h). CONCLUSION: The results confirmed that HSA-EPO fusion gene can be expressed in the CHO cells, with EPO immunogenicity, which could serve as foundation for the development of long-lasting recombinant HSA-EPO protein.

Effect of amino acid residue and oligosaccharide chain chemical modifications on spectral and hemagglutinating activity of Millettia dielsiana Harms. ex Diels. lectin.

The effects of modifying the carbohydrate chain and amino acids on the conformation and activity of Millettia dielsiana Harms. ex Diels. lectin (MDL) were studied by hemagglutination, fluorescence and circular dichroism analysis. The modification of tryptophan residues led to a compete loss of hemagglutinating activity; however, the addition of mannose was able to prevent this loss of activity. The results indicate that two tryptophan residues are involved in the carbohydrate-binding site. Modifications of the carboxyl group residues produced an 80% loss of activity, but the presence of mannose protected against the modification. The results suggest that the carboxyl groups of aspartic and glutamic acids are involved in the carbohydrate-binding site of the lectin. However, oxidation of the carbohydrate chain and modification of the histidine and arginine residues did not affect the hemagglutinating activity of MDL. Fluorescence studies of MDL indicate that tryptophan residues are present in a relatively hydrophobic region, and the binding of mannose to MDL could quench tryptophan fluorescence without any change in lambda(max). The circular dichroism spectrum showed that all of these modifications affected the conformation of the MDL molecule to different extents, except the modification of arginine residues. Fluorescence quenching showed that acrylamide and iodoacetic acids are able to quench 77% and 98% of the fluorescence of tryptophan in MDL, respectively. However, KI produced a barely perceptible effect on the fluorescence of MDL, even when the concentration of I(-) was 0.15 M. This demonstrates that most of tryptophan residues are located in relatively hydrophobic or negatively charged areas near the surface of the MDL molecule.

[Cloning, expression, and alternative splicing of the novel isoform of hTCP11 gene].

OBJECTIVE: To identify a novel isoform of hTCP11 gene and investigate its expression and alternative splicing. METHODS: According to the sequence of human ESTs which are highly homologous to hTCP11a, primers for PCR were synthesized. Then, the amplified fragments were cloned and sequenced; some methods including BLAST, ClustalW and RT-PCR were used for genomic analysis, study of alternative splicing and gene expression among multiple tissues and different testis tissues. RESULTS: A novel isoform of hTCP11 gene was isolated. It encodes a 440 amino acid protein that is highly homologous to the mouse 566 amino acid protein which is important to sperm function because it encodes the receptor for fertilization promoting peptide (FPP). Among TCP11a, TCP11b and TCP11c, the complicated alternative splicing was found. RT-PCR analysis of RNA extracted from human tissues revealed that the gene is only expressed in fertile adult testes, but not in azoospermic patient testes, fetal testes or other human tissues. CONCLUSION: Our results along with the mouse Tcp-11 function suggest that the isoforms of TCP11 gene play important roles in sperm function and fertility.

Identification of a novel human zinc finger protein gene ZNF313.

A novel human zinc finger protein gene that contains both ring finger and C(2)H(2) domain was first isolated by mRNA differential display between the testes of fertile adults and azoospermic patients followed by rapid amplification of cDNA ends (RACE). Total 6 exons of the human gene span a 17,484 bp genomic DNA sequence that was mapped to chromosome 20q13 by fluorescence in situ hybridization. The mature processed mRNA encodes a 228-amino acid protein with a C(3)HC(4) ring finger and three C(2)H(2) domains. Genomic analysis of the human gene identified two polyadenylation signals in exon 6 resulting in alternative 3'-untranslated regions. Results of Northern blot and RT-PCR of RNAs extracted from multiple tissues revealed that the gene has two transcripts of which the shorter transcript was expressed abundantly in fertile adult testes, but much less in testes of azoospermic patient, fetus as well as other human tissues. These data suggest that the gene may play a role in human spermatogenesis and male fertility.

[Cloning, expression and alternative splicing of a novel isoform of human TCP11b gene].

Based on homology analysis and RT-PCR, a novel isoform of human TCP11 gene was isolated. It encodes a 503 amino acid protein that is highly homologous to the mouse 566 amino acid protein Tcp-11. Tcp-11 is important to sperm function because it may be the receptor of fertilization promoting peptide (FPP). Complicated alternative splicing was found to exist between TCP11a and TCP11b genes. The gene has been mapped to human chromosome band 6p21 by fluorescence in situ hybridization. Results of Northern blot and RT-PCR analysis of RNA extracted from human tissues revealed that the gene was expressed in fertile adult testes only, but neither in azoospermic patient testes, fetal testes nor in other human tissues. Our results suggest that TCP11b gene may be important to human sperm function and male fertility.