Florent I C, Raibaud A, Eisen H
Fred Hutchinson Cancer Research Center, Seattle, Washington 98104.
Mol Cell Biol. 1991 Apr;11(4):2180-8. doi: 10.1128/mcb.11.4.2180-2188.1991.
Two genes, belonging to a new expression site-associated gene family of six to eight members in Trypanosoma equiperdum and Trypanosoma brucei, have been cloned from a T. equiperdum variant. One of them, called ESAG-9c, is contained in the 1.78-C expression site and is found just upstream of the 5' barren region. The other one, called ESAG-9u, is unique in the family, is not telomere linked, and apparently is not expression site related. A 2-kb poly(A)+ mRNA is detected with probes for this ESAG-9 family in all T. equiperdum variants examined. By using polymerase chain reaction and restriction fragment length polymorphism techniques, it has been possible to distinguish between ESAG-9c and ESAG-9u and to show that ESAG-9c is transcribed in an expression site-specific manner. However, ESAG-9u (or another gene in the family having identical characteristics) is transcribed in all variants, regardless of the expression site used by these variants. Thus, this ESAG-9 family contains at least one gene that is under expression site control but might have other genes that are not. The function of these ESAG-9 genes is unknown. Transcripts homologous to ESAG-9 were detected in T. brucei bloodstream forms but not in procyclics.
从马媾疫锥虫的一个变种中克隆出了两个基因，它们属于马媾疫锥虫和布氏锥虫中一个新的表达位点相关基因家族，该家族有六到八个成员。其中一个基因名为ESAG - 9c，包含在1.78 - C表达位点中，位于5' 无基因区的上游。另一个基因名为ESAG - 9u，在该家族中是独特的，不与端粒相连，且显然与表达位点无关。在所检测的所有马媾疫锥虫变种中用针对这个ESAG - 9家族的探针检测到了一个2 kb的多聚腺苷酸加尾mRNA。通过使用聚合酶链反应和限制性片段长度多态性技术，得以区分ESAG - 9c和ESAG - 9u，并表明ESAG - 9c以表达位点特异性的方式转录。然而，ESAG - 9u（或该家族中具有相同特征的另一个基因）在所有变种中都有转录，无论这些变种使用的是哪个表达位点。因此，这个ESAG - 9家族至少包含一个受表达位点控制的基因，但可能也有其他不受表达位点控制的基因。这些ESAG - 9基因的功能尚不清楚。在布氏锥虫的血流形式中检测到了与ESAG - 9同源的转录本，但在其前循环体中未检测到。
