Correlation study between prokaryotic ubiquitin-like protein (Pup)-proteasome system of Mycobacterium tuberculosis and persistence of Mycobacterium tuber-culosis / 中国免疫学杂志

ABSTRACT

Objective:To explore the regulation of prokaryotic ubiquitin-like protein ( Pup )-proteasome system on the persistence of Mycobacterium tuberculosis by inducing Mycobacterium tuberculosis to being persistence state under hypoxia conditions and then analyzing the difference on the expression levels of Pup,Dop,PafA and Mpa gene at various time and different conditions. Methods:The total mRNA of the international standard virulent strains of Mycobacterium tuberculosis(H37Rv),which were cultured under hypoxia and aerobic conditions, were extracted from each group at various time and purity of the mRNA were identified.The expression of Pup,Dop,PafA and Mpa genes of M.tuberculosis strains in each group were quantified by SYBR Green I qRT-PCR,which aimed at finding the difference among the expression of Pup,Dop,PafA and Mpa genes at various time and different conditions.Results:The expression levels of Pup, Dop, PafA and Mpa genes in Mycobacterium tuberculosis under hypoxia conditions were measured at various times.The expression levels of Pup,Dop,PafA and Mpa genescompared with the 0 d,the expression of the Pup gene was up-regulated 1.66,2.43 and 2.76-fold at 4 d,7 d,10 d respectively(P<0.05);the expression of the Dop gene was up-regulated 1.38, 1.91,2.54 and 3.28-fold at 2 d,4 d,7 d,10 d respectively(P<0.05);the expression of the PafA gene was up-regulated 1.22,1.75, 2.37 and 2.67-fold at 2 d,4 d,7 d,10 d respectively( P<0.05);the expression of the Mpa gene was up-regulated 1.66,2.21 and 2.63-fold at 4 d,7 d,10 d respectively(P<0.05).Take the aerobic conditions as control,under hypoxic conditions with the same culture time,the expression of the Pup gene was up-regulated 1.85,2.81 and 2.93-fold in 4 d,7 d,10 d respectively(P<0.05);the ex-pression of the Dop gene was up-regulated 1.20,1.76,2.01 and 3.01-fold in 2 d,4 d,7 d,10 d,respectively( P<0.05);the expression of the PafA gene was up-regulated 1.22,1.57,2.29 and 2.29-fold in 2 d,4 d,7 d,10 d,respectively(P<0.05);the expression of the Mpa gene was up-regulated 1.16,1.58,2.16 and 2.69-fold in 2 d,4 d,7 d,10 d,respectively(P<0.05).Conclusion:Under hypoxic conditions,there were significant differences on the expressions of Pup, Dop, PafA and Mpa genes at various times;what′s more, significant differences on the expressions of Pup,Dop,PafA and Mpa genes exist between hypoxic and aerobic conditions at the same time,Prokaryotic ubiquitin-like protein( Pup)-proteasome system plays a regulatory role on M.tuberculosis′s persistence.