Prokaryotic ParA–ParB–parS system links bacterial chromosome segregation with the cell cycle

Abstract

While the essential role of episomal par loci in plasmid DNA partitioning has long been appreciated, the function of chromosomally encoded par loci is less clear. The chromosomal parA-parB genes are conserved throughout the bacterial kingdom and encode proteins homologous to those of the plasmidic Type I active partitioning systems. The third conserved element, the centromere-like sequence called parS, occurs in several copies in the chromosome. Recent studies show that the ParAParB-parS system is a key player of a mitosis-like apparatus ensuring proper intracellular localization of certain chromosomal regions such as oriC domain and their active and directed segregation. Moreover, the chromosomal par systems link chromosome segregation with initiation of DNA replication and the cell cycle. Suggested Reviewers:Opposed Reviewers:Dear Prof. Chattoraj, Please find enclosed the revised version of the review on ParABS chromosomal systems. The manuscript has been modified according to your suggestions. I removed the controversial "mitotic-like" term from the title and replaced it in the text by mitosis-like. I am hoping you will find this version f the review acceptable for publication. Yours sincerely. Grazyna Jagura-Burdzy Cover LetterThe manuscript has been already modified according to reviewers' suggestions in its previous revised version with the exception of "the mitotic-like" term (see below). The controversial "mitotic-like" term has been removed from the title and replaced it in the text by mitosis-like (when appropriate). Additional subtle changes have been introduced according to Editor-in-Chief suggestions. *Response to ReviewsThe review presents up-to-date evidence on the role chromosomally encoded ParAParB-parS systems play in the chromosome segregation in different bacterial species highlighting their function in linking chromosome segregation with initiation of DNA replication and the cell cycle.

Proteasome substrate capture and gate opening by the accessory factor PafE from Mycobacterium tuberculosis

“…Rv3213c is predicted to be a ParA-like protein with ATPase activity. ParA, which is conserved in almost all (if not all) bacterial species, works with a partner protein, ParB, and is involved in chromosome partitioning (19). Numerous ParA homologues are present in many bacterial genomes and do not necessarily work with a ParB-like partner protein.…”

Archaeal Extrachromosomal Genetic Elements

“…Plasmid pNOB8-33 carries a deletion of an ϳ8-kb stretch of sequence, which encodes proteins homologous to the ParA ATPase and ParB DNA-binding protein, components of the bacterial plasmid partitioning and chromosomal segregation system (168). In bacteria, the Par proteins interact with the DNA element parCparS and actively partition the replicated genomes of the plasmid or chromosome (170). Whether the pNOB8 ParA and ParB homologs serve a similar function in Sulfolobus and whether the loss of the parAB genes is responsible for the instability of pNOB8-33 remain to be investigated.…”

Modulation of Bacterial Proliferation as a Survival Strategy

“…In the nonreplicating swarmer cell, the origin is positioned at the flagellated pole; upon replication initiation in the stalked cell, the newly replicated origin is rapidly moved to the opposite cell pole by an active process while the replisome gradually moves to midcell (Viollier et al, 2004). The active mechanism of origin translocation depends on the ParAB-parS system consisting of the ParA ATPase, the ParB DNA-binding protein, and the cis-acting parS sequence (Mierzejewska & Jagura-Burdzy, 2012). ParB binds specifically to the parS site, which is located in proximity to the origin of replication.…”