[Mutation analysis of the PAH gene in children with phenylketonuria from the Qinghai area of China].

OBJECTIVE: To study the mutation characteristics of the phenylalanine hydroxylase (PAH) gene in children with phenylketonuria (PKU) from the Qinghai area of China, in order to provide basic information for genetic counseling and prenatal diagnosis. METHODS: Mutations of the PAH gene were detected in the promoter and exons 1-13 and their flanking intronic sequences of PAH gene by PCR and DNA sequencing in 49 children with PKU and their parents from the Qinghai area of China. RESULTS: A total of 30 different mutations were detected in 80 out of 98 mutant alleles (82%), including 19 missense (63%), 5 nonsense (17%), 3 splice-site (10%) and 3 deletions (10%). Most mutations were detected in exons 3, 6, 7, 11 and intron 4 of PAH gene. The most frequent mutations were p.R243Q (19%), IVS4-1G>A (9%), p.Y356X (7%) and p.EX6-96A>G(5%). Two novel mutations p.N93fsX5 (c.279-282delCATC) and p.G171E (c.512G>A) were found. p.H64fsX9(c.190delC) was documented for the second time in Chinese PAH gene. The mutation spectrum of the gene PAH in the Qinghai population was similar to that in other populations in North China while significantly different from that in the populations from some provinces in southern China, Japan and Europe. CONCLUSIONS: The mutations of PAH gene in the Qinghai area of China demonstrate a unique diversity, complexity and specificity.

[Characteristics of the PAH gene mutation in Chinese patients with phenylketonuria in Xinjiang].

OBJECTIVE: To study the characteristics of the PAH gene mutation in patients with phenylketonuria (PKU) in Xinjiang area. METHODS: The mutations in exons 3, 5, 6, 7, 11 and 12 and the flanking intronic sequence of the PAH gene were detected by PCR/SSCP analysis and direct DNA sequencing in 46 PKU patients. RESULTS: Twenty different mutations were found in 68/92 alleles (73.9%). The prevalent mutations of R243Q, EX6 96A>G, R111X, Y356X and V399V were similar to that of Northern China populations. The mutations F161S, L255S, P281L, and R413P were significantly different from that in other Chinese populations. It was the second time that E280G and A434D mutations were reported in the world, that L255S, P281L, R261Q, and I65T mutations were found in China. Thirteen different mutations were first found in Chinese Uygur, which showed a distinct ethnic characteristics. CONCLUSION: The study showed not only a distinct and conservative, but also a crossed and syncretic genetic characteristics in Xinjiang Uygur population. The results suggest that Xinjiang could be an ideal genetic resource repertoire for studying diversity of gene mutations, heterogeneity of PAH gene, human origins and migration.

[Semen analysis of sterile patients among occupational computermen].

OBJECTIVE: To explore temn possible correlation between the computer occupational semen quality. METHODS: We included in this study 224 sterile males (118 computermen and 106 non-computermen) treated in our clinic of male sterility and 125 normal fertile men as controls, and analyzed such parameters as semen liquefaction time and sperm density, vitality and motility according to the WHO standard. RESULTS: Compared with the normal controls, there was a significant decrease in the semen volume and sperm density, vitality and motility (P < 0.05-0.01) and a marked increase in liquefaction time in the infertile computermen and non-computermen (P < 0.01). The semen volume and sperm vitality and motility were significantly lower in the infertile computermen than in the infertile non-eomputermen (P < 0.05). The three parameters were also significantly decreased in the 0-5, 6-10 and > 10 h/d computer use groups. Similarly, significantly lower sperm density, vitality and motility were observed in the > 10 hid group than in the 0-5 and 6-10 h/d groups (P < 0.05-0.01), but with no statistical difference between the latter two (P > 0.05). CONCLUSION: Computer occupation is associated with abnormal semen quality, and long-term computer use ( > 10 h/d) may be one of the factors of male infertility.

Expression of recombination-activating genes and T cell receptor gene recombination in the human T cell leukemia cell line.

BACKGROUND: Recent studies have suggested that mature T cells can change their specificity through reexpression of recombination-activating genes (RAG) and RAG-mediated V(D)J recombination. This process is named receptor revision and has been observed in mature peripheral T cells from transgenic mice and human donors. However, whether thebreceptor revision in mature T cells is a random or orientated process remains poorly understood. Here we used the Jurkathuman T cell line, which represents a mature stage of T cell development, as a model to investigate the regulation of Tcell receptor (TCR) gene recombination. METHODS: TCR Dbeta-Jbeta signal joint T cell receptor excision DNA circles (sjTRECs) were determined by nested and seminested PCR. Double-strand DNA breaks at recombination signal sequences (RSSs) in the TCRVbeta chain locus were detected by ligation-mediated-PCR. Further analysis of the complementarity-determining region 3 (CDR3) size of the TCRVbeta chain was examined by the TCR GeneScan technique. RESULTS: RAG1, RAG2, and three crucial components of the nonhomologous DNA end-joining (NHEJ) pathway were readily detected in Jurkat. Characteristics of junctional diversity of Dbeta2-Jbeta2 signal joints and ds RSS breaks associated with the Dbeta2 5' and Dbeta 2 3' sites were detected in DNA from Jurkat cells. CDR3 size and the gene sequences of the TCRVbeta chain did not change during cell proliferation. CONCLUSIONS: RAG1 and RAG2 and ongoing TCR gene recombination are coexpressed in Jurkat cells, but the ongoing recombination process may not play a role in modification of the TCR repertoire.However, the results suggest that Jurkat could be used as a model for studying the regulation of RAGs and V(D)J recombination and as a "special" model of the coexistence of TCR gene rearrangements and "negative" receptor revision.

[T cell receptor gene recombination in human T-cell leukemia cell line jurkat].

BACKGROUND & OBJECTIVE: Recently, recombination activating gene (RAG)-mediated transposition has been found to contribute to chromosomal translocation and may be related to the occurrence of lymphoid malignancy; however, the underlying mechanism is unclear. Our previous study showed a co-expression of RAG1 and RAG2 in a human T-cell leukemia cell line Jurkat, which represents a mature stage of T cell development, and that the mRNA levels could be regulated by T cell activators. This study was to determine RAGs-mediated T cell receptor(TCR) gene recombination in Jurkat cells, and thus to provide a new thoughtway for studying the correlations of TCR gene recombination to lymphoid malignancy. METHODS: TCR Dbeta-Jbeta signal joint T-cell receptor excision DNA circles (sjTRECs) were determined by nested and semi-nested polymerase chain reaction (PCR). Double-strand DNA breaks at recombination signal sequences (RSSs) in the TCR beta chain locus were detected by ligation-mediated polymerase chain reaction (LM-PCR). TdT and Ku70/Ku80 were detected by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Characteristics of junctional diversity of Dbeta2-Jbeta2 sjTRECs and ds RSS breaks associated with Dbeta2 5'-site and Dbeta2 3'-site were detected in DNA of Jurkat cells. TdT and Ku70/Ku80 were also detected. CONCLUSION: There is an ongoing TCR gene recombination in Jurkat cells. Jurkat may be used as an ideal cell line model for studying the correlation of TCR gene recombination to lymphoid malignancy.

[Complementarity-determining region 3 analysis of T cell receptor beta chain variable region in peripheral blood mononuclear cells of patients with systemic lupus erythematosus].

OBJECTIVE: To analyze the drift of the complementarity-determining region 3 (CDR3) of T cell receptor (TCR) beta chain variable region (TCR BV) in peripheral blood mononuclear cells (PBMCs) of patients with systemic lupus erythematosus. METHODS: Immunoscope spectratyping techniques was used to analyze the distribution of TCRbeta chain CDR3 in 5 normal blood donors and the dominant CDR3 in the PBMCs in 5 SLE patients. Sequence analysis of the CDR3 region in monoclonal or oligoclonal T cells was performed. RESULTS: The spectratypes of TCR BV gene CDR3 region showed Gaussian distribution in the 5 normal blood donors. The 5 SLE patients, however, displayed anomalous proliferation and oligoclonal expansion of the T cells was observed in different TCR BV families with different CDR3 sequences. CONCLUSION: Noticeable drift of TCRbeta chain CDR3 can be seen in active SLE, indicating possible association of selective expression of TCR with immune pathogenesis in SLE. Determination of specific TCR CDR3 sequence provides a new means for studying the pathogenesis and personalized treatment of SLE.

[Effects of T cell receptor gene rearrangement on BV CDR3 in Jurkat cells].

OBJECTIVE: To investigate the effects of T cell receptor (TCR) BD2-BJ2 gene rearrangement on the complementary-determining region (CDR) 3 of TCR beta chain (TCR BV CDR3) in Jurkat cells. METHODS: TCR BV gene subfamilies were detected by RT-PCR in Jurkat cells during proliferation and after induction with non-specific T cell activators and SEA, respectively. To determine the clonality of TCR BV subfamilies and the lengths of CDR3, the PCR products were analyzed by TCR GeneScan technique, and the sequences of CDR3 were further analyzed by DNA sequencer. RESULTS: No new TCR BV subfamilies were found in Jurkat cells, a monoclonal BV8(+)cell line, either during cell proliferation or after stimulation with different treatments, nor were any differences found in CDR3 size or sequences. CONCLUSION: TCR BD2-BJ2 rearrangement in Jurkat cells may not play a role in modification of TCR BV CDR3 domains or the consequent antigen immunorecognition of BV CDR3, but the possibility of TCR modification can not be excluded.