Kaustuv Sanyal

Jawaharlal Nehru Centre for Advanced Scientific Research | JNCASR · Molecular Biology and Genetics Unit

Candida albicans is the most prevalent fungal pathogen associated with candidemia. Similar to other fungi, the complex life cycle of C. albicans has been challenging to study with high-resolution microscopy due to its small size. We employed ultrastructure expansion microscopy (U-ExM) to directly visualise sub-cellular structures at high resolution...

During chromosome segregation, the spindle assembly checkpoint (SAC) detects errors in kinetochore-microtubule attachments. Timely activation and maintenance of the SAC until defects are corrected is essential for genome stability. Here, we show that SGO1 codes for shugoshin, a tension-sensing protein, that ensures the maintenance of SAC signals in...

Candida auris poses threats to the global medical community due to its multidrug resistance, ability to cause nosocomial outbreaks and resistance to common sterilization agents. Different variants that emerged at different geographical zones were classified as clades. Clade-typing becomes necessary to track its spread, possible emergence of new cla...

The absolute configuration dictates the biological role of chiral molecules in the living world. This is best exemplified by all ribosomally synthesized polypeptides having chiral amino acids only in the l-configuration. However, d-amino acids are also associated with various vital biological processes such as peptidoglycan of the bacterial cell wa...

The Dam1 complex is essential for mitotic progression across evolutionarily divergent fungi. Upon analyzing amino acid (aa) sequences of Dad2, a Dam1 complex subunit, we identified a conserved 10-aa–long Dad2 signature sequence (DSS). An arginine residue (R126) in the DSS is essential for viability in Saccharomyces cerevisiae that possesses point c...

Candida albicans is an opportunistic human pathogen that colonizes the gastrointestinal and genitourinary tracts of healthy individuals. C. albicans yeast cells can switch to filamentous forms. On biotic and abiotic surfaces, the planktonic free-floating yeast cells often form biofilms, a multi-drug-resistant three-dimensional community of yeast an...

Candida auris exhibits high-level resistance to amphotericin B (AmB). Mechanisms such as ergosterol biosynthesis malfunction, oxidative damage mismanagement, and increased drug efflux contribute to AmB resistance in C. auris . In this study, we experimentally evolved two East Asian drug-susceptible clade II isolates of C. auris (P2428 and CBS10913...

Fungi in the basidiomycete genus Malassezia are the most prevalent eukaryotic microbes resident on the skin of human and other warm-blooded animals and have been implicated in skin diseases and systemic disorders. Analysis of Malassezia genomes revealed that key adaptations to the skin microenvironment have a direct genomic basis, and the identific...

Fungi in the basidiomycete genus Malassezia are the most prevalent eukaryotic microbes resident on the skin of human and other warm-blooded animals and have been implicated in skin diseases and systemic disorders. Analysis of Malassezia genomes revealed that key adaptations to the skin microenvironment have a direct genomic basis, and the identific...

The CUG-Ser1 clade-specific histone H3 variant (H3VCTG ) has been reported to be a negative regulator of planktonic to biofilm growth transition in Candida albicans. The preferential binding of H3VCTG at the biofilm gene promoters makes chromatin repressive for biofilm-mode of growth. The two evolutionarily conserved chaperone complexes involved in...

Candida auris exhibits resistance to multiple antifungal drug classes and sterilization agents, posing threats to the immunocompromised worldwide. Among the four major geographical clades, the East Asian clade 2 isolates of C. auris are mostly drug susceptible. In this study, we experimentally evolved one such drug-susceptible isolate for multiple...

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PM Objectives Cell division is a well-regulated process ensuring high fidelity propagation of genetic material to maintain genome stability. A plethora of proteins in distinct cellular pathways, like DNA replication, repair, and segregation contribute to a stable genome. Defects in either of th...

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PM Objectives Candida albicans is an opportunistic fungal pathogen residing as a harmless commensal component of the human microbiota. In the gut, C. albicans efficiently colonizes and successfully competes to limiting nutrient resources and overcomes the detrimental effect of an array of secon...

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PM Objective: Morphological plasticity is one of the key attributes of microbial pathogens contributing to the successful establishment of infection in host tissues. Candida albicans, an opportunistic human fungal pathogen, lives as a commensal in the gut, skin, and genitourinary tracts of most...

Chromosomal instability caused by cell division errors is associated with antifungal drug resistance in fungal pathogens. Here, we identify potential mechanisms underlying such instability by conducting an overexpression screen monitoring chromosomal stability in the human fungal pathogen Candida albicans. Analysis of ~1000 genes uncovers six chrom...

Glutathione, an important redox buffer of the cell, also functions as a source of sulphur and nitrogen under starvation conditions. The metabolism and maintenance of glutathione homeostasis are vital for the appropriate functioning of the cell. In addition to the γ-glutamyl transpeptidase, the fungus-specific alternative pathway involving DUG1, DUG...

Candida auris, the multidrug-resistant human fungal pathogen, emerged as four major distinct geographical clades (clade 1–clade 4) in the past decade. Though isolates of the same species, C. auris clinical strains exhibit clade-specific properties associated with virulence and drug resistance. In this study, we report the identification of unique D...

Shorter centromeres have fewer kinetochore microtubules (kMTs) bound as evident in Saccharomyces cerevisiae where each chromosome is associated with a single kMT. Cells can also be conditioned in recruiting excess kMTs highlighting the flexibility of the kinetochore as the kMT binding interface. Here, we addressed the evolutionary significance of t...

Evolutionarily conserved nucleosome assembly protein Nap1 is involved in multiple cellular processes in eukaryotes. In this study, we wanted to explore the role of Nap1 in the life cycle of rice blast fungus Magnaporthe oryzae. The null mutant of M. oryzae NAP1 is viable. However, deletion of NAP1 leads to defects in growth, appressorium morphology...

Objectives: Echinocandins are frontline antifungal agents in the management of invasive infections due to multi-drug resistant Candida auris . The study aimed to evaluate echinocandin resistance in C. auris isolates of multicentric origin, identify the resistance mechanism, and analyze the pharmacodynamic response to caspofungin in a neutropenic mo...

Asymmetric spindle pole body (SPB) inheritance requires a cascade of events that involve kinases, phosphatases and structural scaffold proteins including molecular motors and microtubule-associated proteins. Higher levels of an SPB component Spc72 and the spindle positioning factor Kar9 at the old SPB, which migrates to the daughter cell, ensure as...

Minichromosome maintenance (Mcm) proteins are well-known for their functions in DNA replication. However, their roles in chromosome segregation are yet to be reviewed in detail. Following the discovery in 1984, a group of Mcm proteins, known as the ARS-nonspecific group consisting of Mcm13, Mcm16-19, and Mcm21-22, were characterized as bonafide kin...

Chromosomal instability in fungal pathogens caused by cell division errors is associated with antifungal drug resistance. To identify mechanisms underlying such instability and to uncover new potential antifungal targets, we conducted an overexpression screen monitoring chromosomal stability in the human fungal pathogen Candida albicans . Analysis...

Chromosomal instability in fungal pathogens caused by cell division errors is associated with antifungal drug resistance. To identify mechanisms underlying such instability and to uncover new potential antifungal targets, we conducted an overexpression screen monitoring chromosomal stability in the human fungal pathogen Candida albicans . Analysis...

DNA replication in eukaryotes is initiated by the orchestrated assembly and association of initiator proteins (heterohexameric Origin Recognition Complex, ORC) on the replication origins. These functionally conserved proteins play significant roles in diverse cellular processes besides their central role in ignition of DNA replication at origins. C...

The dynamic process of mitotic spindle assembly depends on multitudes of inter-dependent interactions involving kinetochores (KTs), microtubules (MTs), spindle pole bodies (SPBs), and molecular motors. Before forming the mitotic spindle, multiple visible microtubule organizing centers (MTOCs) coalesce into a single focus to serve as an SPB in the p...

Shugoshin proteins are evolutionarily conserved across eukaryotes, with some species-specific cellular functions, ensuring the fidelity of chromosome segregation. They act as adaptors at various subcellular locales to mediate several protein-protein interactions in a spatio-temporal manner. Here, we characterize shugoshin (Sgo1) in the human fungal...

Aging is associated with altered mitochondrial function, which is dependent on the magnesium (Mg+2) ion flux. The molecular mechanism underlying Mg+2 homeostasis, especially during aging has not been well understood. We previously demonstrated that the absence of a vacuolar ion transporter Mnr2 accelerates cell death in the older part of the colony...

The thermotolerant multidrug-resistant ascomycete Candida auris rapidly emerged since 2009 causing systemic infections worldwide and simultaneously evolved in different geographical zones. The molecular events that orchestrated this sudden emergence of the killer fungus remain mostly elusive. Here, we identify centromeres in C. auris and related sp...

The thermotolerant multidrug-resistant ascomycete Candida auris rapidly emerged since 2009 and simultaneously evolved in different geographical zones worldwide, causing superficial as well as systemic infections. The molecular events that orchestrated this sudden emergence of the killer fungus remain mostly elusive. Here, we identify centromeres in...

The establishment of centromeric chromatin and its propagation by the centromere-specific histone, CENPA is mediated by epigenetic mechanisms in most eukaryotes. DNA replication origins, origin binding proteins, and replication timing of centromere DNA are important determinants of centromere function. The epigenetically regulated regional centrome...

The microtubule-binding outer kinetochore is coupled to centromeric chromatin through CENP-C Mif2 , CENP-T Cnn1 , and CENP-U Ame1 linker pathways originating from the constitutive centromere associated network (CCAN) of the inner kinetochore. Here, we demonstrate the recurrent loss of most CCAN components, including certain kinetochore linkers duri...

Chromosome segregation during the cell cycle is an evolutionarily conserved, fundamental biological process. Dynamic interaction between spindle microtubules and the kinetochore complex that assembles on centromere DNA is required for faithful chromosome segregation. The first artificial minichromosome was constructed by cloning the centromere DNA...

Shugoshin proteins are evolutionary conserved across eukaryotes with some species-specific cellular functions ensuring the fidelity of chromosome segregation. Shugoshin being present at various subcellular locales, acts as an adaptor to mediate various protein-protein interactions in a spatio-temporal manner. Here, we characterize shugoshin (Sgo1)...

Aging is associated with altered mitochondrial function. Mitochondrial function is dependent on the magnesium (Mg+2) ion flux. The molecular mechanism underlying Mg+2 homeostasis, especially during aging has not been well understood. We previously demonstrated that the absence of a vacuolar ion transporter Mnr2 accelerates cell death in the older p...

Chromosome segregation during the cell cycle is an evolutionarily conserved , fundamental biological process. Dynamic interaction between spindle microtubules and the kinetochore complex that assembles on centromere DNA is required for faithful chromosome segregation. The first artificial minichromosome was constructed by cloning the centromere DNA...

Centromeres of Candida albicans form on unique and different DNA sequences but a closely related species, Candida tropicalis, possesses homogenized inverted repeat (HIR)-associated centromeres. To investigate the mechanism of centromere type transition, we improved the fragmented genome assembly and constructed a chromosome-level genome assembly of...

Centromeres of Candida albicans form on unique and different DNA sequences but a closely related species, Candida tropicalis, possesses homogenized inverted repeat (HIR)-associated centromeres. To investigate the mechanism of centromere type transition, we improved the fragmented genome assembly and constructed a chromosome-level genome assembly of...

Centromeres of Candida albicans form on unique and different DNA sequences but a closely related species, Candida tropicalis, possesses homogenized inverted repeat (HIR)-associated centromeres. To investigate the mechanism of centromere type transition, we improved the fragmented genome assembly and constructed a chromosome-level genome assembly of...

Centromeres are chromosomal regions that serve as platforms for kinetochore assembly and spindle attachments, ensuring accurate chromosome segregation during cell division. Despite functional conservation, centromere DNA sequences are diverse and often repetitive, making them challenging to assemble and identify. Here, we describe centromeres in an...

Aneuploidy is associated with drug resistance in fungal pathogens. In tropical countries, Candida tropicalis is the most frequently isolated Candida species from patients. To facilitate the study of genomic rearrangements in C. tropicalis, we assembled its genome in seven gapless chromosomes by combining next-generation sequencing (NGS) technologie...

Genomic rearrangements associated with speciation often result in chromosome number variation among closely related species. Malassezia species show variable karyotypes ranging between 6 and 9 chromosomes. Here, we experimentally identified all 8 centromeres in M. sympodialis as 3 to 5 kb long kinetochore-bound regions spanning an AT-rich core and...

Positioning the nucleus to a specific cellular location is a prerequisite for high-fidelity transmission of the genetic material to daughter cells. The cellular location of the nucleus just before its division is variable in budding yeast species which rely on a variety of mechanisms for nuclear division. Dynamic growth and shrinkage kinetics of mi...

34 Genomic rearrangements associated with speciation often result in chromosome number 35 variation among closely related species. Malassezia species show variable karyotypes ranging 36 between 6 and 9 chromosomes. Here, we experimentally identified all 8 centromeres in M. 37 sympodialis as 3 to 5 kb long kinetochore-bound regions spanning an AT-ri...

The microtubule-binding outer kinetochore is linked to centromeric chromatin through the inner kinetochore CENP-C Mif2 , CENP-T Cnn1 , and CENP-U Ame1 pathways. These are the only known kinetochore linker proteins across eukaryotes. Linker proteins are structurally less conserved than their outer kinetochore counterparts. Here, we demonstrate the r...

Centromeres are rapidly evolving across eukaryotes, despite performing a conserved function to ensure high-fidelity chromosome segregation. CENP-A chromatin is a hallmark of a functional centromere in most organisms. Due to its critical role in kinetochore architecture, the loss of CENP-A is tolerated in only a few organisms, many of which possess...

Centromeres are chromosomal regions that serve as platforms for kinetochore assembly and spindle attachments, ensuring accurate chromosome segregation during cell division. Despite functional conservation, centromere DNA sequences are diverse and often repetitive, making them challenging to assemble and identify. Here, we describe centromeres in an...

Histone H3 and its variants regulate gene expression but the latter are absent in most ascomycetous fungi. Here, we report the identification of a variant histone H3, which we have designated H3VCTG because of its exclusive presence in the CTG clade of ascomycetes, including Candida albicans, a human pathogen. C. albicans grows both as single yeast...

https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3431419 Centromeres are rapidly evolving across eukaryotes, despite performing a conserved function to ensure high fidelity chromosome segregation. CENP-A chromatin is a hallmark of a functional centromere in most organisms. Due to its critical role in kinetochore architecture, the loss of CENP-A...

Magnaporthe oryzae is an important fungal pathogen that causes a loss of 10% to 30% of the annual rice crop due to the devastating blast disease. In most organisms, kinetochores are clustered together or arranged at the metaphase plate to facilitate synchronized anaphase separation of sister chromatids in mitosis. In this study, we showed that the...

https://www.biorxiv.org/content/10.1101/706580v1.full Centromeres are rapidly evolving across eukaryotes, despite performing a conserved function to ensure high fidelity chromosome segregation. CENP-A chromatin is a hallmark of a functional centromere in most organisms. Due to its critical role in kinetochore architecture, the loss of CENP-A is to...

The dynamic process of mitotic spindle assembly depends on multitudes of inter-dependent interactions involving kinetochores (KTs), microtubules (MTs), spindle pole bodies (SPBs), and molecular motors. Before forming the mitotic spindle, multiple visible microtubule organizing centers (MTOCs) coalesce into a single focus to serve as a SPB in the pa...

Chromatin architecture influences gene expression and makes specialized chromatin domains. Factors including histone variants, histone modifiers and chromatin remodelers that define chromatin architecture impact chromosome related processes in Candida albicans. In this context, we sought to investigate the roles of the ATP-dependent chromatin remod...

Candida albicans, an ascomycete, has an ability to switch to diverse morphological forms. While C. albicans is predominatly diploid, it can tolerate aneuploidy as a survival strategy under stress. Aurora kinase B homolog Ipl1 is a critical ploidy regulator that controls microtubule dynamics and chromosome segregation in Saccharomyces cerevisiae. In...

The diploid budding yeast Candida albicans harbors unique CENPA-rich 3- to 5-kb regions that form the centromere (CEN) core on each of its eight chromosomes. The epigenetic nature of these CENs does not permit the stabilization of a functional kinetochore on an exogenously introduced CEN plasmid. The flexible nature of such centromeric chromatin is...

The poor penetration of anti-fungal agents into the cornea through the intact epithelium layer makes it difficult to treat acute fungal corneal infections. Herein, we developed Amphotret (amphotericin B) antifungal drug contained polycaprolactone-Fe3O4 (PCL-FO) magnetic nanofibers (MNFs) using the electrospinning technique. These MNFs generate heat...

The nuclear division takes place in the daughter cell in the basidiomycetous budding yeast Cryptococcus neoformans. Unclustered kinetochores gradually cluster and the nucleus moves to the daughter bud as cells enter mitosis. Here, we show that the evolutionarily conserved Aurora B kinase Ipl1 localizes to the nucleus upon the breakdown of the nucle...

Candida albicans, an ascomycete, has an ability to switch to diverse morphological forms. While C. albicans is predominatly diploid, it can tolerate aneuploidy as a survival strategy under stress. Aurora kinase B homolog Ipl1 is a critical ploidy regulator that controls microtubule dynamics and chromosome segregation in Saccharomyces cerevisiae. In...

Saccharomyces cerevisiae and Schizosaccharomyces pombe have served as uncontested unicellular model organisms, as major discoveries made in the field of genome biology using yeast genetics have proved to be relevant from yeast to humans. The yeast Candida albicans has attracted much attention because of its ability to switch between a harmless comm...

Genomic rearrangements associated with speciation often result in chromosome number variation among closely related species. Malassezia species show variable karyotypes ranging between 6 and 9 chromosomes. Here, we experimentally identified all 8 centromeres in M. sympodialis as 3 to 5 kb long kinetochore-bound regions spanning an AT-rich core and...

A series of well-synchronized events mediated by kinetochore-microtubule interactions ensure faithful chromosome segregation in eukaryotes. Centromeres scaffold kinetochore assembly and are among the fastest evolving chromosomal loci in terms of the DNA sequence, length, and organization of intrinsic elements. Neither the centromere structure nor t...

The process of centromere formation enables the cell to conserve established genetic and epigenetic information from the previous cell cycle and reuse it for future episodes of chromosome segregation. CENPA asserts the role of an epigenetic requirement in maintaining active centromeres. Active centromeres are subject to position effects which can c...

DNA replication in eukaryotes is initiated by the orchestrated assembly and association of initiator proteins (heterohexameric Origin Recognition Complex, ORC) on the replication origins. These functionally conserved proteins play significant roles in diverse cellular processes besides their central role in ignition of DNA replication at origins. W...

The greater the diversity, the greater the perfection."-Thomas Berry A centromere is classically defined as the primary constriction on a metaphase chromosome [1] that holds the sister chromatids together, binds to spindle microtubules, and brings about their separation during anaphase. Despite having a conserved and essential function, centro-mere...

Candida albicans, a human pathogen, carries an expanded family of Zn(II)2Cys6 transcription factors. A CTG clade-specific protein Zcf32 and its closely related protein Upc2, a well-conserved transcription factor across the various fungal species, belong to this family of proteins. Unlike Upc2, Zcf32 is poorly studied in C. albicans. Here, we examin...