TY - JOUR
T1 - Cloning, sequencing, and expression of the mig gene of Mycobacterium avium, which codes for a secreted macrophage-induced protein
AU - Plum, Georg
AU - Brenden, Martina
AU - Clark-Curtiss, Josephine E.
AU - Pulverer, Gerhard
PY - 1997
Y1 - 1997
N2 - Mycobacterium avium is an intracellular pathogen that has evolved to be a frequent cause of disseminated infection in immunocompromised patients. Although these bacilli are readily phagocytized, they are able to survive and even multiply within human macrophages. The process whereby mycobacteria circumvent the lytic functions of the macrophages is currently not well understood, but this is a key aspect in the pathogenicity of all pathogenic mycobacteria. Previously, we identified a gene in M. avium, designated mig (for macrophage-induced gene), the expression of which is induced when the bacilli grow in human macrophages (G. Plum and J. E. Clark-Curtiss, Infect. Immun. 62:476-483, 1994). In the present study we show that (i) the nucleotide sequence of the mig gene has an open reading frame of 295 amino acids with a strong bias for mycobacterial codon usage, (ii) the mig gene also codes for a putative signal peptide of 19 amino acid residues, (iii) mig is induced by acidity to be expressed as an early-secreted 30-kDa protein, and (iv) the Mig protein exhibits an AMP-binding domain signature. However, beyond this motif which is common to enzymes that activate a large variety of substrates, no homologics to known sequences are found. We also show that (v) Mycobacterium smegmatis strains expressing the Mig protein have a limited advantage for survival in macrophages. These findings may be concordant with a role of the mig gene in the virulence of M. avium.
AB - Mycobacterium avium is an intracellular pathogen that has evolved to be a frequent cause of disseminated infection in immunocompromised patients. Although these bacilli are readily phagocytized, they are able to survive and even multiply within human macrophages. The process whereby mycobacteria circumvent the lytic functions of the macrophages is currently not well understood, but this is a key aspect in the pathogenicity of all pathogenic mycobacteria. Previously, we identified a gene in M. avium, designated mig (for macrophage-induced gene), the expression of which is induced when the bacilli grow in human macrophages (G. Plum and J. E. Clark-Curtiss, Infect. Immun. 62:476-483, 1994). In the present study we show that (i) the nucleotide sequence of the mig gene has an open reading frame of 295 amino acids with a strong bias for mycobacterial codon usage, (ii) the mig gene also codes for a putative signal peptide of 19 amino acid residues, (iii) mig is induced by acidity to be expressed as an early-secreted 30-kDa protein, and (iv) the Mig protein exhibits an AMP-binding domain signature. However, beyond this motif which is common to enzymes that activate a large variety of substrates, no homologics to known sequences are found. We also show that (v) Mycobacterium smegmatis strains expressing the Mig protein have a limited advantage for survival in macrophages. These findings may be concordant with a role of the mig gene in the virulence of M. avium.
UR - http://www.scopus.com/inward/record.url?scp=0030809876&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030809876&partnerID=8YFLogxK
U2 - 10.1128/iai.65.11.4548-4557.1997
DO - 10.1128/iai.65.11.4548-4557.1997
M3 - Article
C2 - 9353032
AN - SCOPUS:0030809876
SN - 0019-9567
VL - 65
SP - 4548
EP - 4557
JO - Infection and immunity
JF - Infection and immunity
IS - 11
ER -