CAJ | 학술논문

转座子是宿主基因组的重要组成部分.Ty3/gypsy 反转座子是广泛存在于生物体内的一类反转座子.通过反向PCR(inverse PCR)和基因组步移方法成功地从二化螟体内获得一个具有完整结构的 Ty3/gypsy 反转座子拷贝,命名为Csu-Ty3(GenBank 登录号：KJ191261).该反转座子拷贝全长4934 bp,在基因组上插入的靶位点(target sit duplications, TSDs)是“AACGT”,两端的长末端重复序列(long terminal repeat,LTR)不完全相同,5′端 LTR 长161 bp,3′端 LTR 长168 bp,两者的一致度为93．5％；在靠近3′端 LTR 处有一段长15 bp 的嘌呤尾(polypurine tract,PPT)序列.经 ORF Finder 分析,Csu-Ty3中包含三个独立的 ORF,从左至右第一个 ORF 编码类似病毒的结构蛋白,称为 GAG 蛋白；第二个 ORF 编码天冬氨酰蛋白酶(aspartic protease,AP)蛋白；第三个 ORF 编码一个多聚蛋白,包含反转录酶(reverse transcriptase,RT)、RNA酶 H(RNase H,RH)以及整合酶(integrase,IN).Southern 杂交显示二化螟不同地理种群中均有较多的 Csu-Ty3拷贝.在特定基因座位上,对 Csu-Ty3拷贝插入与否的检测结果显示,二化螟不同地理种群中在该位点上均含有 Csu-Ty3拷贝的插入,但在德阳和江津种群中有些个体在该位点上没有检测到 Csu-Ty3拷贝的插入.
전좌자시숙주기인조적중요조성부분.Ty3/gypsy 반전좌자시엄범존재우생물체내적일류반전좌자.통과반향PCR(inverse PCR)화기인조보이방법성공지종이화명체내획득일개구유완정결구적 Ty3/gypsy 반전좌자고패,명명위Csu-Ty3(GenBank 등록호：KJ191261).해반전좌자고패전장4934 bp,재기인조상삽입적파위점(target sit duplications, TSDs)시“AACGT”,량단적장말단중복서렬(long terminal repeat,LTR)불완전상동,5′단 LTR 장161 bp,3′단 LTR 장168 bp,량자적일치도위93．5％；재고근3′단 LTR 처유일단장15 bp 적표령미(polypurine tract,PPT)서렬.경 ORF Finder 분석,Csu-Ty3중포함삼개독립적 ORF,종좌지우제일개 ORF 편마유사병독적결구단백,칭위 GAG 단백；제이개 ORF 편마천동안선단백매(aspartic protease,AP)단백；제삼개 ORF 편마일개다취단백,포함반전록매(reverse transcriptase,RT)、RNA매 H(RNase H,RH)이급정합매(integrase,IN).Southern 잡교현시이화명불동지리충군중균유교다적 Csu-Ty3고패.재특정기인좌위상,대 Csu-Ty3고패삽입여부적검측결과현시,이화명불동지리충군중재해위점상균함유 Csu-Ty3고패적삽입,단재덕양화강진충군중유사개체재해위점상몰유검측도 Csu-Ty3고패적삽입.
Transposable elements constitute a substantial fraction of host genomes.Ty3/gypsy retrotransposon,one group of LTR retrotransposons,is widespread in different species.By inverse-PCR and genome walking,a novel member of Ty3/gypsy retrotransposons was cloned from Chilo suppressalis .This new member of Ty3/gypsy retrotransposons was named Csu-Ty3 (GenBank accession No.KJ1 9 126 1 ).The sequence is 4 934 bp in length and integrated into the “AACGT”target site duplications (TSDs)of the genome.There is a pair of non-completely identical long terminal repeats (LTRs)in the Csu-Ty3 retrotransposon.The 5′LTR is 1 6 1 bp in length and the 3′LTR is 1 68 bp,sharing 93?5 % similarities.A polypurine tract (PPT),1 5 bp in length,is adjacent to the 3′LTR.There are three independent open reading frames (ORFs)in Csu-Ty3.The first ORF encodes a protein which is related to viral structural protein,termed GAG.The second encodes aspartic protease (AP).The third encodes a polyprotein including a reverse transcriptase (RT)which produces a cDNA copy of the transposon′s RNA,an RNase H (RH)which splits the DNA-RNA hybrid and an integrase (IN ) which inserts the cDNA into the host′s genome.The southern hybridization indicated that there were many Csu-Ty3 copies in different C .suppressalis populations.Flanking PCR results showed that the Csu-Ty3 copy was inserted at the same locus in different populations.At this locus,all the individuals have the Csu-Ty3 copy insertion except some individuals from Deyang and Jiangjin populations.The Csu-Ty3 insertion ratio varied with field populations.