Conserved cysteine and histidine residues in the putative zinc finger motif of the influenza A virus M1 protein are not critical for influenza virus replication

• Published in: Journal of general virology Vol. 84; no. 11; pp. 3105 - 3113
• Main Authors: Hui, Eric Ka-Wai, Ralston, Katherine, Judd, Amrit K, Nayak, Debi P
• Format: Journal Article
• Language: English
• Published: England Soc General Microbiol 01.11.2003
• Subjects: Amino Acid Motifs; Amino Acid Sequence; Conserved Sequence; Cysteine; double prime M1 protein; Histidine; Influenza A virus; Influenza A virus - chemistry; Influenza A virus - physiology; Molecular Sequence Data; Structure-Activity Relationship; Viral Matrix Proteins - chemistry; Virus Replication; Zinc Fingers
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/vir.0.19389-0

1 Department of Microbiology, Immunology and Molecular Genetics, Jonsson Comprehensive Cancer Center, Molecular Biology Institute, UCLA School of Medicine, Los Angeles, CA 90095, USA 2 SynVax Inc., North Logan, UT 84341, USA Correspondence Debi P. Nayak dnayak{at}ucla.edu The influenza virus matrix protein (M1) possesses a cysteine and histidine (CCHH) motif in the helix 9 (H9) and adjacent region ( 148 C AT C EQIADSQ H RS H 162 ). The CCHH motif has been proposed as a putative zinc finger motif and zinc-binding activity has been implicated in virus uncoating as well as transcription inhibition and mRNA regulation. The function of the CCHH motif in the influenza virus life cycle was investigated by site-directed mutagenesis (alanine replacement) and by rescuing mutant viruses by reverse genetics. Mutant viruses containing an alanine replacement of the cysteine and histidine residues, either individually or in combination, were seen to exhibit wt phenotype in multiple virus growth cycles and plaque morphology. In addition, synthetic peptides containing the putative zinc finger motif did not inhibit virus replication in MDCK cells. However, mutation of Ala 155 in H9 was lethal for rescuing infectious virus. These data show that the CCHH motif does not provide a critical function in the influenza virus life cycle in cell culture and that the zinc-binding function may not be involved in virus biology. However, the lethal phenotype of the Ala 155 mutation shows that the H9 region of M1 provides some other critical function(s) in virus replication.