Research on chromosome number variation in Vibrio cholerae

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K07551
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 49050:Bacteriology-related
• Research Institution: National Institute of Infectious Diseases
• Principal Investigator: Yamamoto Shouji 国立感染症研究所, 細菌第一部, 主任研究官 (80469957)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: コレラ菌 / 染色体数 / 増殖能 / 生息環境 / 外来性遺伝子

Outline of Final Research Achievements

The number of chromosomes in V. cholerae has been thought to be two, but recently, strains in which two chromosomes are fused into single chromosome have been identified. This study was conducted to elucidate the mechanism of chromosome number variation and its role in survival strategies, and the following findings were obtained: 1) An experimental system was established to monitor chromosome number variation in V. cholerae, and a single chromosome strain, V060002, was successfully separated from single to two chromosomes; 2) The strain with two chromosomes grew faster at low temperatures (25°C) than the strain with single chromosome; 3) Vibrio Genomic Island 1 (VGI1), a gene cluster encoded in the genome of V060002, was suggested to be involved in chromosome singularization.

Free Research Field

細菌学　分子遺伝学

Academic Significance and Societal Importance of the Research Achievements

本研究では初めてコレラ菌の1本の染色体を２本に分離することに成功するとともに、同一の遺伝的背景において染色体数の違いのみの影響を解析することが可能な実験系を確立した。その結果、２本の染色体をもつ株の方が１本の染色体を持つ株に比べてコレラ菌の生息環境に近い25℃での増殖能が高いことが判明し、コレラ菌が２本の染色体もつことの意義を提案することができた。また、コレラ菌の染色体は外来性遺伝子の獲得によって１本になる場合があることを明らかにした。