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目的 :分析和比较早产儿和足月儿免疫球蛋白重链可变区 (IgH)基因中的可变区基因片段 (VH)、多样化基因片段 (D)和连接区基因片段 (JH)的使用 ,VH 上的体突变 ,在VH D和D JH 连接点插入的NDN长度以及开放性阅读框 (ORF)等特征及其差异性。方法 :7例胎龄为 2 5 30周的早产儿和 8例胎龄为 37 41周的足月儿的脐带单核细胞DNA被抽提 ,使用套式PCR扩增IgH基因 ,扩增产物被克隆筛选和测序。结果 :在早产儿 ,共有 2 0个不同的VH 被使用 ,其中DP73(V3 家族成员 )被最优先使用 ,使用率为 2 1.4% ,其次是DP75 (V1家族成员 ) ,使用率为 19.0 % ,VH 上有少数体突变 ( 16 .7% )。JH6和JH3使用率分别为 42 .8%和 41.7% ,J1未被使用。IgH重排基因的VH D JH 连接点处偶有N区插入 ,DND长度为 15 .5± 7.3bp。6 4 3%的IgH基因序列具有开放性阅读框。在足月儿 ,32个不同的VH 被使用 ,DP73和DP75的使用率分别降到 11.6 %和8.3 % ,VH 上的突变为 2 9.2 %。JH6和JH3使用率分别降至 19.3 %和 34.1% ,J1仍未被使用。IgH重排基因的VH-D -JH 连接点处有少量N区插入 ,DND为 2 2 .6± 6 .8bp。 91.7%IgH基因序列的阅读框是开放的。结论 :胎龄 2 5周以上的早产儿已有IgH重排基因 ,且大部分处于活化状态 ,但由于VH 和JH 的偏倚使用 ,N
OBJECTIVE: To analyze and compare the variable region gene fragment (VH), diversified gene fragment (D) and junctional region gene fragment (JH) in preterm infant and term immunoglobulin heavy chain variable region (IgH) Use, bulk mutation on VH, length of NDN inserted at the VH D and D JH junctions, and open reading frames (ORFs), among others, and their variability. METHODS: DNA from umbilical cord mononuclear cells from 7 preterm infants with a gestational age of 25-30 weeks and full term infants with 37 41 weeks gestational age were extracted and the IgH gene was amplified using nested PCR. The amplified product was Clone screening and sequencing. RESULTS: In preterm infants, a total of 20 different VHs were used, of which DP73 (a member of the V3 family) was most preferentially used at a rate of 21.4%, followed by DP75 (a member of the V1 family) with a 19.0% Minority-like mutations in VH (16.7%). JH6 and JH3 were used at 42.8% and 41.7%, respectively, and J1 was not used. The Ig D JH junction of the IgH rearranged gene was inserted with an occasional N-region, with a DND of 15.5 ± 7.3 bp. 6 4 3% of the IgH gene sequence has an open reading frame. In term infants, 32 different VHs were used, and the rates of DP73 and DP75 decreased to 11.6% and 8.3%, respectively, with a VH of 22.9%. JH6 and JH3 usage dropped to 19.3% and 34.1%, respectively, while J1 remained unutilized. The IgH rearranged gene has a small number of N-region insertions at the VH-D-JH junction with a DND of 226.28 bp. The reading frame of 91.7% IgH gene sequence is open. CONCLUSIONS: IgH rearrangement genes are present in preterm infants with gestational age of more than 25 weeks, and most are activated, but due to the biased use of VH and JH, N