Abuladze N K, Gingery M, Tsai J, Eiserling F A
Department of Microbiology and Molecular Genetics, University of California, Los Angeles 90024.
Virology. 1994 Mar;199(2):301-10. doi: 10.1006/viro.1994.1128.
This report identifies a protein that regulates tail length in bacteriophage T4. Earlier work (Duda et al., 1990) suggested that the gene 29 protein could be involved in T4 tail length determination as a "template" or "tape-measure", similar to that proposed for the gene H protein in bacteriophage lambda. We have altered the length of a recombinant gene 29 by constructing deletions and duplications in different parts of the gene. Each of these constructs was incorporated into the high-level expression vector, pET-11d. Seven plasmids with different lengths of gene 29 were made and used in complementation studies. We have found that the length of the tail can be decreased by deleting the C-terminal part of gene 29 or increased by forming duplications in different parts of this gene, and that the length of the tail can be proportional to the size of the engineered protein. Unlike phage lambda, plasmids with deletions in the middle of gene 29 or from the N-terminal end produced correspondingly smaller but inactive gene 29 protein and no viable phage were formed. Our results show that alterations in the length of gene 29 protein proportionately alters tail length, and argue strongly for a scheme in which 29 protein is a ruler or template that determines tail length during tail assembly.
本报告鉴定出一种调节噬菌体T4尾部长度的蛋白质。早期研究（Duda等人，1990年）表明，基因29蛋白可能作为“模板”或“卷尺”参与T4尾部长度的决定，类似于噬菌体λ中基因H蛋白的作用。我们通过在基因的不同部位构建缺失和重复序列来改变重组基因29的长度。将这些构建体分别导入高效表达载体pET-11d中。制备了7种含有不同长度基因29的质粒，并用于互补研究。我们发现，通过缺失基因29的C末端部分可使尾部长度缩短，通过在该基因的不同部位形成重复序列可使尾部长度增加，并且尾部长度与工程化蛋白的大小成比例。与噬菌体λ不同，在基因29中间或N末端有缺失的质粒产生相应较小但无活性的基因29蛋白，且未形成有活力的噬菌体。我们的结果表明，基因29蛋白长度的改变会相应地改变尾部长度，有力地支持了一种观点，即29蛋白是在尾部组装过程中决定尾部长度的尺子或模板。
