• Journal of Microbiology and Biotechnology
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• v.33 no.11
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• pp.1420-1427
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• 2023

The forkhead domain genes are important for development and morphogenesis in fungi. Six forkhead genes fkhA-fkhF have been found in the genome of the model filamentous Ascomycete Aspergillus nidulans. To identify the fkh gene(s) associated with fungal development, we examined mRNA levels of these six genes and found that the level of fkhB and fkhD mRNA was significantly elevated during asexual development and in conidia. To investigate the roles of FkhB and FkhD, we generated fkhB and fkhD deletion mutants and complemented strains and investigated their phenotypes. The deletion of fkhB, but not fkhD, affected fungal growth and both sexual and asexual development. The fkhB deletion mutant exhibited decreased colony size with distinctly pigmented (reddish) asexual spores and a significantly lower number of conidia compared with these features in the wild type (WT), although the level of sterigmatocystin was unaffected by the absence of fkhB. Furthermore, the fkhB deletion mutant produced sexual fruiting bodies (cleistothecia) smaller than those of WT, implying that the fkhB gene is involved in both asexual and sexual development. In addition, fkhB deletion reduced fungal tolerance to heat stress and decreased trehalose accumulation in conidia. Overall, these results suggest that fkhB plays a key role in proper fungal growth, development, and conidial stress tolerance in A. nidulans.

• The Korean Journal of Mycology
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• v.38 no.2
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• pp.160-166
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• 2010

A homothallic filamentous fungus Aspergillus nidulans has been used as the a model organism for studying growth and development for eukaryotic system. Various studies about specific transcription factors have been performed for elucidating the molecular mechanisms of growth, asexual and sexual developmental processes. Among them, the fkhE gene (AN2025.3) is located in chromosome VII and contains an ORF encoding 718 amino acid polypeptide intervening with two short introns. The cDNA sequencing revealed that at least four types of alternative splicing events were occurred when the fkhE gene was transcribed. The putative FkhE polypeptide contains a conserved forkhead domain and a bipartite nuclear localization signal at it's N-terminus and C-terminus, respectively. Deletion of fkhE resulted in impaired conidiophore formation in a solid medium. However, the sexual developmental process or cleistothecia formation was normal. Furthermore, fkhE deletion mutant produced conidiophores and conidia under the submerged culture, indicating that the fkhE gene is involved in asexual developmental process similar to the fkhF gene.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.4
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• pp.499-509
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• 2008

Foxo1 plays an important role in the integration of hormone-activated signaling pathways with the complex transcriptional cascade that promotes preadipocyte differentiation of clonal cell lines from rodents. We isolated the full-length cDNA of porcine FoxO1 gene using RACE, confirmed by visual Northern blotting. The deduced amino acids indicated 94% and 90% identities with the corresponding human and mice aa. Analysis of the aa sequence, showed that it included a Forkhead domain (aa 167-247), a transmembrane structure domain (aa 90-113), a LXXLL motif (aa 469-473), and 51 Ser, 8 Thr, and 4 Tyr phosphorylation sites, indicating a potential important role for FoxO1 transcriptional activity in vivo. Using the IMpRH panel, we mapped FoxO1 gene to chromosome 11p13. Our data provide basic molecular information useful for the further investigation on the function of FoxO1 gene. Time-course analysis of FoxO1 expressions indicated that levels of mRNA and protein gradually increased from day 0 to 3, and it reached almost maximal level at day 3, then decreased from day 5 to 7 in porcine primary preadipocyte differentiation. After induction by IGF-1, GPDH activity and accumulation of lipid increased, however, expressions of FoxO1 mRNA and protein were inhibited in a dose dependent manner. These results suggest that FoxO1 takes part in porcine preadipocyte differentiation and expressions of FoxO1 were regulated by IGF-1.

• International Journal of Oncology
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• v.54 no.6
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• pp.2169-2178
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• 2019

Forkhead box A1 (FOXA1) functions as a tumor suppressor gene or an oncogene in various types of cancer; however, the distinct function of FOXA1 in colorectal cancer is unclear. The present study aimed to evaluate whether FOXA1 affects the oncogenic behavior of colorectal cancer cells, and to investigate its prognostic value in colorectal cancer. The impact of FOXA1 on tumor cell behavior was investigated using small interfering RNA and the pcDNA6-myc vector in human colorectal cancer cell lines. To investigate the role of FOXA1 in the progression of human colorectal cancer, an immunohistochemical technique was used to localize FOXA1 protein in paraffin-embedded tissue blocks obtained from 403 patients with colorectal cancer. Tumor cell apoptosis and proliferation were evaluated using a terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay and Ki-67 immunohistochemical staining, respectively. FOXA1 knockdown inhibited tumor cell invasion in colorectal cancer cells, and induced apoptosis and cell cycle arrest. FOXA1 knockdown activated cleaved caspase-poly (ADP-ribose) polymerase, upregulated the expression of p53 upregulated modulator of apoptosis, and downregulated BH3 interacting domain death agonist and myeloid cell leukemia-1, leading to the induction of apoptosis. FOXA1 knockdown increased the phosphorylation level of signal transducer and activator of transcription-3. By contrast, these results were reversed following the overexpression of FOXA1. The overexpression of FOXA1 was associated with differentiation, lymphovascular invasion, advanced tumor stage, depth of invasion, lymph node metastasis and poor survival rate. The mean Ki-67 labeling index value of FOXA1-positive tumors was significantly higher than that of FOXA1-negative tumors. However, no significant association was observed between the expression of FOXA1 and the mean apoptotic index value. These results indicate that FOXA1 is associated with tumor progression via the modulation of tumor cell survival in human colorectal cancer.

• Journal of Microbiology
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• v.43 no.6
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• pp.523-528
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• 2005

Using the genomic library constructed at the downstream of the niiA promoter, which induces the over-expression of an inserted DNA fragment, we have attempted to screen the genes affecting growth or development by over-expression. The wild-type strain was transformed using the AMA-niiA(p) library and cultured on 1.2 M sorbitol media, in which asexual sporulation is induced, but sexual development is repressed. Over 100,000 strains transformed to $pyrG^+$ were analyzed with regard to any changes in phenotype. Consequently, seven strains were isolated for further analyses. These strains were designated NOT [niiA(p) over-expression transformants] stains. Four of the strains were of the inducible type, and the remaining strains were of the multi-copy suppression type. Two of the inducible-type strains, NOT 1 and NOT40, harbored genes which had been inserted in reverse direction, suggesting that the mutant phenotypes had been derived from an excess amount of anti-sense mRNA. Domain analyses of the deduced polypeptides from the DNA fragments rescued from the transformants revealed that NOT1, NOT40 and NOT6 harbored a LisH motif, a forkhead domain, and a $Zn(II)_2Cys_6$ binuclear zinc cluster, respectively.

• Development and Reproduction
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• v.14 no.2
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• pp.91-97
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• 2010

FOXL2 is a winged-helix/forkhead (FH) domain transcription factor, and mutations in FOXL2 gene are responsible for blepharophimosis-ptosis-epicanthus inversus syndrome (BPES). BPES is an autosomal dominant genetic disease. BPES type I patients exhibit both premature ovarian failure (POF) and eyelid malformation, while only the eyelid defect is observed in BPES type II. FOXL2-null ovaries showed a blockage of granulosa cell differentiation, suggesting that FOXL2 plays an essential role for proper ovarian folliculogenesis. Previously, we screened for FOXL2-interacting proteins and identified steroidogenic factor-1 (SF-1) which is known to be required for gonad development and transactivates steroidogenic enzymes including CYP19. In the present study, we demonstrated that FOXL2 transactivates CYP19 and stimulated the transcriptional activation of CYP19 induced by SF-1. In contrast, FOXL2 mutants found in BPES type I and II exhibited compromised abilities to enhance CYP19 induction mediated by SF-1. Thus, this study provides a functional difference between wild-type FOXL2 and its mutants which may aid to understand pathophysiology of BPES elicited by FOXL2 mutations.