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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Infectious Agents and Disease
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1390371

Identification of a putative α-galactoside β-(1→3)-galactosyltransferase involved in the biosynthesis of glucronoxylomannogalactan galactomannan side chain in Cryptococcus neoformans

Provisionally accepted
Chihiro Kadooka Chihiro Kadooka 1*Yutaka Tanaka Yutaka Tanaka 2Daisuke Hira Daisuke Hira 1Takuji Oka Takuji Oka 1
  • 1 Sojo University, Kumamoto, Japan
  • 2 Tohoku Medical and Pharmaceutical University, Sendai, Miyagi, Japan

The final, formatted version of the article will be published soon.

    Cell surface of Cryptococcus neoformans is covered by a thick capsular polysaccharide. The capsule is the most important virulence factor of C. neoformans; however, the complete mechanism of its biosynthesis is unknown. The capsule is composed of glucuronoxylomannan (GXM) and glucuronoxylomannogalactan (GXMGal). As GXM is the most abundant component of the capsule, many studies have focused on GXM biosynthesis. However, although GXMGal has an important role in virulence, studies on its biosynthesis are scarce. Herein, we have identified a GT31 family β-(1→3)-galactosyltransferase Ggt2, which is involved in the biosynthesis of the galactomannan side chain of GXMGal. Comparative analysis of GXMGal produced by a ggt2 disruption strain revealed that Ggt2 is a glycosyltransferase that catalyzes the initial reaction in the synthesis of the galactomannan side chain of GXMGal. The ggt2 disruption strain showed a temperature-sensitive phenotype at 37°C, indicating that the galactomannan side chain of GXMGal is important for high temperature stress tolerance in C. neoformans. Our findings provide insights into complex capsule biosynthesis in C. neoformans.

    Keywords: Cryptococcus neoformans, GALACTOSYLTRANSFERASE, glucronoxylomannogalactan, polysaccharide, virulence factor

    Received: 23 Feb 2024; Accepted: 07 May 2024.

    Copyright: © 2024 Kadooka, Tanaka, Hira and Oka. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Chihiro Kadooka, Sojo University, Kumamoto, Japan

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