The Analysis Of The Ubiquitin Genes And Its Flanks Of Monascus Aurantiacus AS3.4384

Ubiquitin (Ub) is a highly conserved 76 amino acid protein present in all eukaryotic organisms either as a free molecule or covalenly attached to lysines in a wide vaiety of proteins. The polyubiquitin gene and the ubiquitin extension gene are two kinds of the ubiquitin genes. In fungi, the ubiqitin gene is found in the process of protein degradation, signal transit, transcriptional regulation, posttranslational processing and secondary metabolite biosynthesis.Monascus, a typical filamentous fungus, is an important microorganism resource of China, which is originated from China a thousand years ago, has been recorded in ancient articles. Recently, some metabolic products, which are produced by Monascus, have been found with important physiological activity. Citrinin, however, a mycotoxin that does harm to humans and animals, was isolated from most cultures of Monascus strains recently. Analysing the genes of Monascus that deal with citrinin and constructing Monascus strains without excreting citrinin by genic engineering technology is the effective way to suppress the excretion of citrinin. Citrinin is a secondary metabolite. The ubiquitin gene is likely belong to biosynthesis pathway of citrinin. In this paper the ubiquitin genes and its flanks of Monascus anrantiacus AS3.4384 were analysed and a M. aurantiacus AS3.4384 genomic library was constructed. The main research results are as follows:1 The ubiquitin gene of M. aurantiacus AS3.4384 was cloned by Southern blotting, using Y₁₃₀ of SSH as the probe that is the ubiqitin gene EST. The result of sequencing indicates that there are both the polyubiquitin genes and the ubiquitin extension genes in M. aurantiacus AS3.4384 genomic DNA.2 Three clones U2, U3,U6 which contain the ubiquitin genes were analysed. The checkpoint protein kinase gene which deals with mitotic spindle checkpoint wasfound in the ubiquitin gene's flank of U2. The cell polarity protein gene which deals with polar budding pseudohypal growth was found in the ubiquitin gene's flank of U3.