Pak J W, Jeon K W
Cell Biology Laboratory, BCMB, University of Tennessee, Knoxville 37996, USA.
Gene. 1996 May 24;171(1):89-93. doi: 10.1016/0378-1119(96)00016-9.
Gram-symbiotic bacteria (called X-bacteria), present in the xD strain of Amoeba proteus as required cell components, synthesize and export a large amount of a 29-kDa protein, S29x. S29x is exported into the host's cytoplasm across the bacterial membranes and the symbiosome membrane. The complete nucleotide (nt) sequence of the s29x gene of X-bacteria has been determined, and the promoter sequence and tsp have also been identified. The gene has a nonconventional promoter with putative nt sequences different from the known consensus sequences. When Escherichia coli cells are transformed with s29x, the gene is expressed and the product is secreted into the culture medium. Functions of S29x are not fully known, but it is suspected that S29x plays an important role in the symbiotic relationship between amoebae and X-bacteria.
革兰氏共生细菌（称为X细菌）作为必需的细胞成分存在于变形虫的xD菌株中，合成并分泌大量29 kDa的蛋白质S29x。S29x通过细菌膜和共生体膜被分泌到宿主细胞质中。已确定X细菌s29x基因的完整核苷酸（nt）序列，并且还鉴定了启动子序列和转录终止位点。该基因具有非常规启动子，其推定的nt序列与已知的共有序列不同。当用s29x转化大肠杆菌细胞时，该基因被表达，产物被分泌到培养基中。S29x的功能尚不完全清楚，但怀疑S29x在变形虫与X细菌之间的共生关系中起重要作用。
