CAJ | 학술논문

对8个节瓜( Benincasa hispida var. chieh-qua How)品系基因组DNA中的Ty1-copia类逆转座子逆转录酶核苷酸序列进行扩增,并对品系A39FA的29个克隆产物的核苷酸序列及翻译的氨基酸序列的系统进化和同源性进行了分析,还对29条氨基酸序列进行了比对。扩增结果表明：8个节瓜品系的基因组DNA中均包含长度约260 bp的逆转录酶核苷酸片段；从品系 A39FA 中获得的29条 Ty1-copia 类逆转座子逆转录酶核苷酸序列( CqRt1至CqRt29)的长度为247~267 bp,同源率为46.2%~98.1%,而它们的氨基酸序列同源率为26.7%~98.8%。序列分析结果表明：节瓜Ty1-copia类逆转座子逆转录酶核苷酸序列中碱基A、T、G和C的数量分别为65~96、47~92、45~74和32~49,所有序列均富含碱基A和T,AT/GC比为1.35~2.33；缺失突变是造成节瓜Ty1-copia类逆转座子逆转录酶核苷酸序列长度差异的主要因素,在序列长度和碱基组成方面的明显差异表明节瓜Ty1-copia类逆转座子逆转录酶核苷酸序列具有高度异质性。翻译后的氨基酸序列中有21条序列存在终止密码子突变、12条序列存在移框突变,表明Ty1-copia类逆转座子是节瓜基因组内序列重组的热点。通过聚类分析可将29个逆转录酶核苷酸序列分为5个家族( Family),分别包括16、4、4、4和1条序列,其中Family 1可能是具有转座活性的逆转座子家族,但存在转录活性的逆转录酶序列仅占全部序列数量的20.69%。将每一家族中的1~2条序列与其他15种植物的Ty1-copia类逆转座子逆转录酶的氨基酸序列进行比对,显示出较高的同源性。研究结果表明：节瓜与其他植物的Ty1-copia类逆转座子可能有相同起源,而且Ty1-copia类逆转座子可在不同类群间横向传递。
대8개절과( Benincasa hispida var. chieh-qua How)품계기인조DNA중적Ty1-copia류역전좌자역전록매핵감산서렬진행확증,병대품계A39FA적29개극륭산물적핵감산서렬급번역적안기산서렬적계통진화화동원성진행료분석,환대29조안기산서렬진행료비대。확증결과표명：8개절과품계적기인조DNA중균포함장도약260 bp적역전록매핵감산편단；종품계 A39FA 중획득적29조 Ty1-copia 류역전좌자역전록매핵감산서렬( CqRt1지CqRt29)적장도위247~267 bp,동원솔위46.2%~98.1%,이타문적안기산서렬동원솔위26.7%~98.8%。서렬분석결과표명：절과Ty1-copia류역전좌자역전록매핵감산서렬중감기A、T、G화C적수량분별위65~96、47~92、45~74화32~49,소유서렬균부함감기A화T,AT/GC비위1.35~2.33；결실돌변시조성절과Ty1-copia류역전좌자역전록매핵감산서렬장도차이적주요인소,재서렬장도화감기조성방면적명현차이표명절과Ty1-copia류역전좌자역전록매핵감산서렬구유고도이질성。번역후적안기산서렬중유21조서렬존재종지밀마자돌변、12조서렬존재이광돌변,표명Ty1-copia류역전좌자시절과기인조내서렬중조적열점。통과취류분석가장29개역전록매핵감산서렬분위5개가족( Family),분별포괄16、4、4、4화1조서렬,기중Family 1가능시구유전좌활성적역전좌자가족,단존재전록활성적역전록매서렬부점전부서렬수량적20.69%。장매일가족중적1~2조서렬여기타15충식물적Ty1-copia류역전좌자역전록매적안기산서렬진행비대,현시출교고적동원성。연구결과표명：절과여기타식물적Ty1-copia류역전좌자가능유상동기원,이차Ty1-copia류역전좌자가재불동류군간횡향전체。
Nucleotide sequence of reverse transcriptase of Ty1-copia-like retrotransposon in genomic DNA from eight lines of Benincasa hispida var. chieh-qua How was amplified, system evolution and homology of nucleotide sequence and translated amino acid sequence of 29 cloning products obtained from line A39FA were analyzed, and 29 amino acid sequences were aligned. The amplification results show that genomic DNA from eight lines of B. hispida var. chieh-qua all includes reverse transcriptase nucleotide fragment with length about 260 bp. Length of 29 nucleotide sequences (from CqRt1 to CqRt29)of reverse transcriptase of Ty1-copia-like retrotransposon obtained from line A39 FA is 247-267 bp with homologous rate of 46 . 2%-98 . 1%, while homologous rate of their amino acid sequences is 26 . 7%-98 . 8%. The sequence analysis results show that number of base A, T, G and C in nucleotide sequence of reverse transcriptase of Ty1-copia-like retrotransposon from B. hispida var. chieh-qua is 65-96, 47-92, 45-74 and 32-49, respectively. All sequences are rich in base A and T, and AT/GC ratio is 1. 35-2 . 33 . Deletion mutation is the main reason inducing differences in length of nucleotide sequence of reverse transcriptase of Ty1-copia-like retrotransposon from B. hispida var. chieh-qua, and obvious differences in sequence length and base composition indicate that there is high heterogeneity in nucleotide sequence of reverse transcriptase of Ty1-copia-like retrotransposon from B. hispida var. chieh-qua. There is stop codon mutation in 21 sequences and frame shift mutation in 12 sequences from translated amino acid sequence, which indicates that Ty1-copia-like retrotransposon is the hot spot in sequence recombination within B. hispida var. chieh-qua genome. 29 nucleotide sequences of reverse transcriptase can be divided into 5 families, containing 16, 4, 4, 4 and 1 sequences, respectively. Family 1 might be a retrotransposon family with transposition activity, while number of reverse transcriptase sequence with transposition activity only accounts for 20 . 69% of total number of sequences . The alignment result on 1-2 amino acid sequences in each family of Ty1-copia-like retrotransposons from B. hispida var. chieh-qua and that of other 15 species shows higher homology. It is indicated that B. hispida var. chieh-qua and other species may possess the same origin, and Ty1-copia-like retrotransposon can be horizontally transferred among different taxa.