Inactivation of deoxyadenosine methyltransferase (dam) attenuates Haemophilus influenzae virulence.
Inactivation of deoxyadenosine methyltransferase (dam) attenuates Haemophilus influenzae virulence.
复制标题
脱氧腺苷甲基转移酶 (dam) 失活可减弱流感嗜血杆菌的毒力。
DOI：
10.1111/j.1365-2958.2004.04140.x
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发表时间：
2004
影响因子：
3.6
通讯作者：
Smith,ArnoldL
中科院分区：
文献类型：
--
作者：
WatsonJr,MichaelE;Jarisch,Justin;Smith,ArnoldL
Mutants in deoxyadenosine methyltransferase (dam) from many Gram‐negative pathogens suggest multiple roles for Dam methylase: directing post‐replicative DNA mismatch repair to the correct strand, guiding the temporal control of DNA replication and regulating the expression of multiple genes (including virulence factors) by differential promoter methylation. Dam methylase (HI0209) in strain Rd KW20 was inactivated inHaemophilus influenzaestrains Rd KW20, Strain 12 and INT‐1; restriction with Dam methylation‐sensitive enzymesDpnI andDpnII confirmed the absence of Dam methylation, which was restored by complementation with a single copy ofdamectopically expressedin cis.Despite the lack of increased mutation frequency, thedammutants had a 2‐aminopurine‐susceptible phenotype that could be suppressed by secondary mutations inmutS, suggesting a role for Dam inH. influenzaeDNA mismatch repair. Invasion of human brain microvascular endothelial cells (HBMECs) and human respiratory epithelial cells (NCI‐H292) by thedammutants was significantly attenuated in all strains, suggesting the absence of a Dam‐regulated event necessary for uptake or invasion of host cells. Intracellular replication was inhibited only in the Strain 12dammutant, whereas in the infant rat model of infection, the INT‐1dammutant was less virulent. Dam activity appears to be necessary for bothin vitroandin vivovirulence in a strain‐dependent fashion and may function as a regulator of gene expression including virulence factors.
