Nishida, Kei et al. (2021) International Worm Meeting "Distinct properties of broadly-expressed and tissue-specific tubulin isotypes examined by ectopic and heterologous expression"

Onodera, Shizuka, Tsuchiya, Kenta, Nishida, Kei, Honda, Yu, Sugimoto, Asako, Ikeda, Masanori, Haruta, Nami, Tanaka, Kozo, Obinata, Hiroyuki

[International Worm Meeting, 2021]

Most organisms have multiple alpha- and beta-tubulin isotypes that likely contribute to the diversity of microtubule (MT) functions. To understand the functional differences of tubulin isotypes in Caenorhabditis elegans, which has nine alpha-tubulin isotypes and six beta-tubulin isotypes, we systematically constructed null mutants and GFP-fusion strains for all tubulin isotypes with the CRISPR/Cas9 system and quantitatively analyzed their expression patterns and levels in adult hermaphrodites. Four isotypes-a-tubulins TBA-1 and TBA-2 and b-tubulins TBB-1 and TBB-2-were expressed in virtually all tissues, with a distinct tissue-specific spectrum. Other isotypes were expressed in specific tissues or cell types at significantly lower levels than the broadly expressed isotypes. Thus, MTs in C. elegans are mainly composed of four broadly expressed tubulin isotypes, and incorporation of a small amount of tissue-specific isotypes may contribute to tissue-specific MT properties. Three alpha-tubulin isotypes (TBA-5, TBA-6, TBA-9) and one beta-tubulin isotype (TBB-4) were expressed in different subsets of ciliated sensory neurons. When each of the ciliated neuron-specific isotypes was ectopically expressed in early embryos, they were less efficiently incorporated into mitotic spindle MTs than broadly-expressed isotypes and affected MT dynamics. The low incorporation efficiency was slightly improved when the ciliated neuron-specific alpha-tubulins were co-expressed with TBB-4, implying that some specific combinations of alpha- and beta-tubulin isotypes form heterodimers preferably incorporated into MTs. The lower MT incorporation efficiencies of these ciliated neuron-specific tubulin isotypes were also observed by their heterologous expression in human cultured cells. Taken together, we speculate that a small amount of ciliated neuron-specific tubulins isotypes is incorporated into MTs mainly formed by broadly-expressed isotypes, which contribute to the cell-type-specific MT properties.

Yanase S et al. (2010) Aging, Metabolism, Stress, Pathogenesis, and Small RNAs, Madison, WI "Some sod gene; targets of DAF-16 transcription factor in Caenorhabditis elegans"

Yanase S, Yazaki K

[Aging, Metabolism, Stress, Pathogenesis, and Small RNAs, Madison, WI, 2010]

DAF-16, a forkhead-type transcription factor, function in downstream of an insulin/insulin-like growth factor-1 (Ins/IGF-1) signaling pathway, and is related to regulation of aging and oxidative stress resistance in the nematode Caenorhabditis elegans (C. elegans). In the latest report, we described that a consensus DAF-16 binding element (DBE), which binds the DAF-16 transcription factor, was discovered in the promoter region of sod-5 gene encoding a Cu/Zn superoxide dismutase (SOD) in C. elegans. The DBE position was 192 base pairs (bp) upstream of the first exon of sod-5 gene from the C. elegans genomic database. In a daf-16 gene null mutant, daf-16(mgDf50) strain, the sod-5 gene expression as well as sod-3 gene was obviously suppressed compared with it in wild-type N2. The phenotype of lifespan in daf-16(mgDf50) animals was reduced when compared with N2. Therefore, it is suggested that sod-5 gene expression is necessary to maintain the lifespan in wild-type with sod-3 gene during normal aging. In addition, we could not find a functional compensation by sod-1 gene in the sod-5 deletion mutant such as the compensatory expression of sod-5 gene via the Ins/IGF-1 signaling pathway in the sod-1 deletion mutants (1). sod-1 gene might have considerable capacity in the expression during the C. elegans normal aging. Thus, it is assumed that the Ins/IGF-1 signaling pathway plays more important role to epigenetic regulation of the target genes under aging and stressful conditions. Reference 1. Yanase S, Onodera A, Tedesco P, Johnson TE, Ishii N (2009) SOD-1 deletions in Caenorhabditis elegans alter localization of intracellular reactive oxygen species and show molecular compensation. J Geront 64A: 530-539.