Institute of Veterinary Medicine, University of Göttingen, Göttingen, Germany.
Biol Reprod. 2013 Feb 7;88(2):29. doi: 10.1095/biolreprod.112.103168. Print 2013 Feb.
Circulating nucleic acids (CNAs) are free-floating, cell-free DNA and RNA molecules in the circulation of healthy and diseased humans and animals. The aim of this study was to identify differences in CNA distribution in serum samples from multiparous pregnant (n = 24) and nonpregnant (n = 16) dairy cows at different days of gestation (Days 0, 20, and 40). A modified serial analysis of gene expression procedure was used to generate concatemerized short sequence tags from isolated serum DNA. A total of 6.1 × 10(6) tags were recovered from analyzed samples (n = 40). Significant differences between the pregnant and nonpregnant groups were detected in chromosomal regions, protein-coding sequences, and single genes (P < 0.05). Approximately 23% (1.4 × 10(6) tags) of the total sequence pool were present exclusively in the analyzed serum samples of pregnant cows. Of these tag sequences, seven originated from genomic regions and 13 from repetitive elements. Comparative BLAST analysis identified the repetitive tags as BovB (non-long terminal repeat retrotransposons/long interspersed nuclear elements), Art2A, BovA2, and Bov-tA2 (short interspersed nuclear elements). To our knowledge, this is the first study to comprehensively characterize the circulating, cell-free DNA profile in sera from pregnant and nonpregnant cows across early gestation.
循环核酸（CNAs）是游离于健康和患病人体和动物循环中的无细胞游离 DNA 和 RNA 分子。本研究旨在鉴定多胎妊娠（n = 24）和非妊娠（n = 16）奶牛在妊娠不同天数（0、20 和 40 天）的血清样本中 CNA 分布的差异。使用改良的基因表达序列分析程序从分离的血清 DNA 生成串联短序列标签。从分析的样本（n = 40）中回收了 6.1 × 10（6）个标签。在染色体区域、蛋白编码序列和单个基因中检测到妊娠组和非妊娠组之间存在显著差异（P < 0.05）。大约 23%（1.4 × 10（6）个标签）的总序列库仅存在于妊娠奶牛的分析血清样本中。这些标签序列中有七个来自基因组区域，13 个来自重复元件。比较 BLAST 分析将重复标签鉴定为 BovB（非长末端重复反转录转座子/长散布核元件）、Art2A、BovA2 和 Bov-tA2（短散布核元件）。据我们所知，这是首次全面描述妊娠和非妊娠奶牛在早期妊娠期间血清中循环无细胞 DNA 图谱的研究。
