Van Wert S L, Yoder O C
Department of Plant Pathology, Cornell University, Ithaca, NY 14853.
Curr Genet. 1994 Mar;25(3):217-22. doi: 10.1007/BF00357165.
GPD1 (encoding glyceraldehyde-3-phosphate dehydrogenase) is a constitutively expressed gene in Cochliobolus heterostrophus that produces a single transcript. The steady state level of GPD1 mRNA is 14-fold greater than that of the constitutively-expressed TRP1 gene (encoding a tryptophan biosynthesis enzyme) indicating that GPD1 has a stronger promoter and/or a more stable mRNA. A set of lacZ translational fusion vectors was constructed to compare the gene expression signals of GPD1, TRP1 and PRO1 (a C. heterostrophus genomic fragment selected for promoter activity) in C. heterostrophus as single copies at the same site in the chromosome. Under conditions that repressed endogenous beta-galactosidase expression, beta-galactosidase activity in transformants was constitutive and required the GPD1, TRP1 or PRO1 expression signals. In-frame GPD1::lacZ activities were 6-fold greater than in-frame TRP1::lacZ and PRO1::lacZ activities, indicating that GPD1 has more efficient expression signals.
GPD1（编码甘油醛-3-磷酸脱氢酶）是玉米小斑病菌中一个组成型表达的基因，产生单一转录本。GPD1 mRNA的稳态水平比组成型表达的TRP1基因（编码一种色氨酸生物合成酶）高14倍，这表明GPD1具有更强的启动子和/或更稳定的mRNA。构建了一组lacZ翻译融合载体，以比较GPD1、TRP1和PRO1（一个因启动子活性而选择的玉米小斑病菌基因组片段）在玉米小斑病菌中作为染色体上同一位点的单拷贝时的基因表达信号。在内源β-半乳糖苷酶表达受到抑制的条件下，转化体中的β-半乳糖苷酶活性是组成型的，并且需要GPD1、TRP1或PRO1表达信号。框内GPD1::lacZ活性比框内TRP1::lacZ和PRO1::lacZ活性高6倍，表明GPD1具有更有效的表达信号。
