Reassessment of germline heavy chain transcripts from two murine VH families.
Reassessment of germline heavy chain transcripts from two murine VH families.
复制标题
重新评估两个小鼠 VH 家族的种系重链转录本。
DOI：
10.1016/s0161-5890(97)00084-9
复制
发表时间：
1997
影响因子：
3.6
通讯作者：
Smith,EA
中科院分区：
文献类型：
--
作者：
Webb,CF;Dou,S;Buchanan,KL;Resta,R;Smithson,G;Smith,EA
虽然功能性重链免疫球蛋白mRNA的表达需要可变（VH）、多样性（D）和（JH）基因区段的重排，但这些单独的基因区段可以在其重排之前转录。有人提出，由此产生的生殖系，或不育，成绩单在重排过程中发挥了重要作用，因为重排频率和不育的转录水平之间的强相关性已在一些研究中观察到。根据编码序列的同源性，小鼠VH基因被分为不同的家族。VH家族以发育调节的方式重排，使得来自几个VH家族的基因重排比J558家族基因重排更早被检测到。巧合的是，唯一的VH家族不育转录本已被记录是J558家族。我们使用RT-PCR分析，以询问是否从其他VH家族的无菌转录本可以检测到胎儿肝脏样本之前，他们的重排。虽然很容易检测到J558家族生殖系转录本，但没有从S107家族观察到不育转录本。我们的研究还揭示了少量降解的基因组DNA非特异性地引发cDNA合成的能力，强调了在解释家族特异性寡核苷酸用于cDNA生产的RT-PCR数据时需要谨慎。这些结果对不育转录本是VHDJH重排所必需的这一观点提出了质疑。
While expression of functional heavy chain immunoglobulin mRNA requires rearrangement of variable (VH), diversity (D) and (JH) gene segments, these individual gene segments can be transcribed prior to their rearrangement. It has been proposed that the resulting germline, or sterile, transcripts play an important role in the rearrangement process because strong correlations between rearrangement frequency and sterile transcript levels have been observed in some studies. Murine VHgenes have been grouped into families on the basis of coding sequence homology. VH families rearrange in a developmentally regulated manner, so that rearrangements of genes from several VHfamilies are detected earlier than rearrangements of J558 family genes. Paradoxically, the only VHfamily for which sterile transcripts have been documented is the J558 family. We used RT-PCR analyses to ask whether sterile transcripts from other VHfamilies could be detected in fetal liver samples prior to their rearrangement. While J558 family germline transcripts were easily detected, no sterile transcripts were observed from the S107 family. Our studies also revealed the ability of small quantities of degraded genomic DNA to nonspecifically prime cDNA synthesis, emphasizing the need for caution in interpreting RT-PCR data in which family-specific oligos are used for cDNA production. These results cast doubt on the idea that sterile transcripts are required for VHDJHrearrangement.