Nitasaka E, Yamazaki T
Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan.
Heredity (Edinb). 1994 Dec;73 ( Pt 6):608-15. doi: 10.1038/hdy.1994.168.
To characterize the relationship between P element activities and their structures, we cloned P elements from genomic libraries of three isogenic P and Q strains derived from natural populations in Japan. These P elements were mapped with BamHI, AvaII and PstI and were classified by their size. The majority of P elements cloned were classified as either complete or relatively small P elements rather than medium size. The numbers of full length (2.9 kb) P elements per haploid genome of NP280 (P), AK194 (weak P) and WY113 (Q) were at least four, five and one, respectively. However, the 2.9 kb P element of WY113 was thought to be defective since this strain has no transposase activity. In our previous work, we demonstrated that the ORF 3-deleted P element is essential for P cytotype determination in WY113. A similar P element also exists in NP280, and this may have an important role for P cytotype determination in this strain. Two and one copies of the KP element, a deletion derivative of the P element, were found in NP280 and AK194, respectively. One of four complete P elements in NP280 was fully sequenced, and the base sequence was completely identical to that of p pi 25.1 originally derived from the U.S.A. This result is consistent with the notion that these P elements have a relatively recent origin in Drosophila melanogaster.
为了描述P因子活性与其结构之间的关系，我们从源自日本自然种群的三个同基因P和Q品系的基因组文库中克隆了P因子。这些P因子用BamHI、AvaII和PstI进行图谱分析，并根据其大小进行分类。克隆得到的大多数P因子被归类为完整的或相对较小的P因子，而非中等大小的P因子。NP280（P）、AK194（弱P）和WY113（Q）单倍体基因组中全长（2.9 kb）P因子的数量分别至少为4个、5个和1个。然而，WY113的2.9 kb P因子被认为是有缺陷的，因为该品系没有转座酶活性。在我们之前的工作中，我们证明了缺失ORF 3的P因子对于WY113中P细胞型的确定至关重要。NP280中也存在类似的P因子，这可能在该品系的P细胞型确定中发挥重要作用。在NP280和AK194中分别发现了2个和1个KP因子（P因子的缺失衍生物）。对NP280中四个完整P因子之一进行了全序列测定，其碱基序列与最初源自美国的p pi 25.1完全相同。这一结果与这些P因子在黑腹果蝇中起源相对较新的观点一致。
