Collins J, Brüning H J
Gene. 1978 Oct;4(2):85-107. doi: 10.1016/0378-1119(78)90023-9.
A plasmid which contains a cos site of lambda and can be packaged into lambda bacteriophage particles is termed a "cosmid". Such plasmids can be used as gene cloning vectors in conjunction with an in vitro packaging system. The properties of a new series of cosmids based on the ColE1 replicon are described, including small temperature-sensitive plasmids which have lost mobilisation functions and carry no IS sequences. Amongst these plasmids are vectors for XmaI, BglII, BamHI, HindIII, PstI, KpnI, SalI and EcoRI. It is demonstrated that by using cosmids in particular size ranges these plasmids provide a high efficiency cloning system which yields essentially only hybrid clones without resort to a second selection or screening step, and without prior modification (e.g. phosphatase) treatment of the DNA. Attempts were made to optimise the cloning properties of the cosmid system. An Escherichia coli "gene bank" was obtained with an efficiency of 5 . 10(5) clones per microgram of E. coli DNA, and in which any particular unselected marker may be found in about one out of every 400 clones. It was demonstrated that deletion of mobilisation functions leads to loss of ability to form relaxation-complex without affecting copy number or segregation properties of the temperature-sensitive derivatives. The vectors are amplifiable in chloramphenicol to make up about 50% of the total cellular DNA.
含有λ噬菌体粘性末端位点且能被包装到λ噬菌体颗粒中的质粒被称为“粘粒”。这类质粒可与体外包装系统一起用作基因克隆载体。本文描述了一系列基于ColE1复制子的新型粘粒的特性，包括已丧失转移功能且不携带插入序列的小型温度敏感型质粒。这些质粒中包括XmaI、BglII、BamHI、HindIII、PstI、KpnI、SalI和EcoRI的载体。结果表明，通过使用特定大小范围的粘粒，这些质粒提供了一种高效克隆系统，该系统基本上只产生杂交克隆，无需进行二次选择或筛选步骤，也无需对DNA进行预先修饰（如磷酸酶处理）。人们试图优化粘粒系统的克隆特性。获得了一个大肠杆菌“基因文库”，其效率为每微克大肠杆菌DNA产生5×10⁵个克隆，在该文库中，任何特定的未选择标记大约每400个克隆中就有一个。结果表明，转移功能的缺失会导致形成松弛复合体的能力丧失，但不影响温度敏感衍生物的拷贝数或分离特性。这些载体可在氯霉素中扩增，使其占细胞总DNA的约50%。
