RESUMEN

The SRY HMG box transcription factor Sox21 plays multiple critical roles in neurogenesis, with its function dependent on concentration and developmental stage. In the allotetraploid Xenopus laevis, there are two homeologs of sox21, namely sox21.S and sox21.L. Previous studies focused on Sox21.S, but its amino acid sequence is divergent, lacking conserved poly-A stretches and bearing more similarity with ancestral homologs. In contrast, Sox21.L shares higher sequence similarity with mouse and chick Sox21. To determine if Sox21.S and Sox21.L have distinct functions, we conducted gain and loss-of-function studies in Xenopus embryos. Our studies revealed that Sox21.S and Sox21.L are functionally redundant, but Sox21.L is more effective at driving changes than Sox21.S. These results also support our earlier findings in ectodermal explants, demonstrating that Sox21 function is dose-dependent. While Sox21 is necessary for primary neuron formation, high levels prevent their formation. Strikingly, these proteins autoregulate, with high levels of Sox21.L reducing sox21.S and sox21.L mRNA levels, and decreased Sox21.S promoting increased expression of sox21.L. Our findings shed light on the intricate concentration-dependent roles of Sox21 homeologs in Xenopus neurogenesis.

Asunto(s)

RESUMEN

Rapid information processing in the central nervous system requires the myelination of axons by oligodendrocytes. The transcription factor Sox2 and its close relative Sox3 redundantly regulate the development of myelin-forming oligodendrocytes, but little is known about the underlying molecular mechanisms. Here, we characterized the expression profile of cultured oligodendroglial cells during early differentiation and identified Bcas1, Enpp6, Zfp488 and Nkx2.2 as major downregulated genes upon Sox2 and Sox3 deletion. An analysis of mice with oligodendrocyte-specific deletion of Sox2 and Sox3 validated all four genes as downstream targets in vivo. Additional functional assays identified regulatory regions in the vicinity of each gene that are responsive to and bind both Sox proteins. Bcas1, Enpp6, Zfp488 and Nkx2.2 therefore likely represent direct target genes and major effectors of Sox2 and Sox3. Considering the preferential expression and role of these genes in premyelinating oligodendrocytes, our findings suggest that Sox2 and Sox3 impact oligodendroglial development at the premyelinating stage with Bcas1, Enpp6, Zfp488 and Nkx2.2 as their major effectors.

Asunto(s)

RESUMEN

SoxB1 transcription factors (Sox2/3) are well known for their role in early neural fate specification in the embryo, but little is known about functional roles for SoxB1 factors in non-neural ectodermal cell types, such as the neural plate border (NPB). Using Xenopus laevis, we set out to determine whether SoxB1 transcription factors have a regulatory function in NPB formation. Here, we show that SoxB1 factors are necessary for NPB formation, and that prolonged SoxB1 factor activity blocks the transition from a NPB to a neural crest state. Using ChIP-seq, we demonstrate that Sox3 is enriched upstream of NPB genes in early NPB cells and in blastula stem cells. Depletion of SoxB1 factors in blastula stem cells results in downregulation of NPB genes. Finally, we identify Pou5f3 factors as potential Sox3 partners in regulating the formation of the NPB and show that their combined activity is needed for normal NPB gene expression. Together, these data identify a role for SoxB1 factors in the establishment and maintenance of the NPB, in part through partnership with Pou5f3 factors.

Asunto(s)

RESUMEN

INTRODUCTION: Sulfur-oxidizing bacteria (SOB) play a key role in the biogeochemical cycling of sulfur. OBJECTIVES: To explore SOB diversity, distribution, and physicochemical drivers in five volcanic lakes and two springs in the Wudalianchi volcanic field, China. METHODS: This study analyzed microbial communities in samples via high-throughput sequencing of the soxB gene. Physical-chemical parameters were measured, and QIIME 2 (v2019.4), R, Vsearch, MEGA7, and Mothur processed the data. Alpha diversity indices and UPGMA clustering assessed community differences, while heat maps visualized intra-sample variations. Canoco 5.0 analyzed community-environment correlations, and NMDS, Adonis, and PcoA explored sample dissimilarities and environmental factor correlations. SPSS v.18.0 tested for statistical significance. RESULTS: The diversity of SOB in surface water was higher than in springs (more than 7.27 times). We detected SOB affiliated to ß-proteobacteria (72.3 %), α-proteobacteria (22.8 %), and γ-proteobacteria (4.2 %) distributed widely in these lakes and springs. Rhodoferax and Cupriavidus were most frequent in all water samples, while Rhodoferax and Bradyrhizobium are dominant in surface waters but rare in springs. SOB genera in both habitats were positively correlated. Co-occurrence analysis identified Bradyrhizobium, Blastochloris, Methylibium, and Metyhlobacterium as potential keystone taxa. Redundancy analysis (RDA) revealed positive correlations between SOB diversity and total carbon (TC), Fe2+, and total nitrogen (TN) in all water samples. CONCLUSION: The diversity and community structure of SOB in volcanic lakes and springs in the Wudalianchi volcanic group were clarified. Moreover, the diversity and abundance of SOB decreased with the variation of water openness, from open lakes to semi-enclosed lakes and enclosed lakes.

RESUMEN

Introduction: The remarkable diversity observed in the structure and development of the molluscan nervous system raises intriguing questions regarding the molecular mechanisms underlying neurogenesis in Mollusca. The expression of SoxB family transcription factors plays a pivotal role in neuronal development, thereby offering valuable insights into the strategies of neurogenesis. Methods: In this study, we conducted gene expression analysis focusing on SoxB-family transcription factors during early neurogenesis in the gastropod Lymnaea stagnalis. We employed a combination of hybridization chain reaction in situ hybridization (HCR-ISH), immunocytochemistry, confocal microscopy, and cell proliferation assays to investigate the spatial and temporal expression patterns of LsSoxB1 and LsSoxB2 from the gastrula stage to hatching, with particular attention to the formation of central ring ganglia. Results: Our investigation reveals that LsSoxB1 demonstrates expanded ectodermal expression from the gastrula to the hatching stage, whereas expression of LsSoxB2 in the ectoderm ceases by the veliger stage. LsSoxB1 is expressed in the ectoderm of the head, foot, and visceral complex, as well as in forming ganglia and sensory cells. Conversely, LsSoxB2 is mostly restricted to the subepithelial layer and forming ganglia cells during metamorphosis. Proliferation assays indicate a uniform distribution of dividing cells in the ectoderm across all developmental stages, suggesting the absence of distinct neurogenic zones with increased proliferation in gastropods. Discussion: Our findings reveal a spatially and temporally extended pattern of SoxB1 expression in a gastropod representative compared to other lophotrochozoan species. This prolonged and widespread expression of SoxB genes may be interpreted as a form of transcriptional neoteny, representing a preadaptation to prolonged neurogenesis. Consequently, it could contribute to the diversification of nervous systems in gastropods and lead to an increase in the complexity of the central nervous system in Mollusca.

RESUMEN

Water bodies are frequently polluted, with sulfur oxides being the most common form of water pollution. Therefore, developing a detection mechanism for sulfur oxides in water bodies is particularly urgent. A new fluorescent probe YX-KZBD was designed and developed. This probe releases fluorescent signals with its own sulfurous acid recognition site, detects sulfurous acid based on the Michael addition reaction, and evaluates the pollution degree of sulfur oxides in the water environment through the transformation mode of the sulfur cycle. This probe has high energy transfer efficiency in aqueous solutions. In addition, the fluorescence data obtained by analyzing the water samples were linearly fitted with the gene abundance values of the functional genes of sulfur-producing bacteria, and a significant correlation was obtained. The Kriging interpolation model was used to evaluate the sulfate content distribution at each sampling point to understand the distribution of sulfur oxides in natural water intuitively. The fluorescence signal excited by the probe was also combined with a real-time quantitative polymerase chain reaction (qPCR), and sulfate-reducing and sulfur-oxidizing bacteria were introduced in the sulfur cycle, providing a new method to assess the extent of water pollution effectively.

Asunto(s)

RESUMEN

In terrestrial hot springs, some members of the microbial mat community utilize sulfur chemical species for reduction and oxidization metabolism. In this study, the diversity and activity of sulfur-metabolizing bacteria were evaluated along a temperature gradient (48-69 °C) in non-acidic phototrophic mats of the Porcelana hot spring (Northern Patagonia, Chile) using complementary meta-omic methodologies and specific amplification of the aprA (APS reductase) and soxB (thiosulfohydrolase) genes. Overall, the key players in sulfur metabolism varied mostly in abundance along the temperature gradient, which is relevant for evaluating the possible implications of microorganisms associated with sulfur cycling under the current global climate change scenario. Our results strongly suggest that sulfate reduction occurs throughout the whole temperature gradient, being supported by different taxa depending on temperature. Assimilative sulfate reduction is the most relevant pathway in terms of taxonomic abundance and activity, whereas the sulfur-oxidizing system (Sox) is likely to be more diverse at low rather than at high temperatures. Members of the phylum Chloroflexota showed higher sulfur cycle-related transcriptional activity at 66 °C, with a potential contribution to sulfate reduction and oxidation to thiosulfate. In contrast, at the lowest temperature (48 °C), Burkholderiales and Acetobacterales (both Pseudomonadota, also known as Proteobacteria) showed a higher contribution to dissimilative sulfate reduction/oxidation as well as to thiosulfate metabolism. Cyanobacteriota and Planctomycetota were especially active in assimilatory sulfate reduction. Analysis of the aprA and soxB genes pointed to members of the order Burkholderiales (Gammaproteobacteria) as the most dominant and active along the temperature gradient for these genes. Changes in the diversity and activity of different sulfur-metabolizing bacteria in photoautotrophic microbial mats along a temperature gradient revealed their important role in hot spring environments, especially the main primary producers (Chloroflexota/Cyanobacteriota) and diazotrophs (Cyanobacteriota), showing that carbon, nitrogen, and sulfur cycles are highly linked in these extreme systems.

RESUMEN

Schistosome helminths infect over 200 million people across 78 countries and are responsible for nearly 300,000 deaths annually. However, our understanding of basic genetic pathways crucial for schistosome development is limited. The sex determining region Y-box 2 (Sox2) protein is a Sox B type transcriptional activator that is expressed prior to blastulation in mammals and is necessary for embryogenesis. Sox expression is associated with pluripotency and stem cells, neuronal differentiation, gut development, and cancer. Schistosomes express a Sox-like gene expressed in the schistosomula after infecting a mammalian host when schistosomes have about 900 cells. Here, we characterized and named this Sox-like gene SmSOXS1. SmSoxS1 protein is a developmentally regulated activator that localizes to the anterior and posterior ends of the schistosomula and binds to Sox-specific DNA elements. In addition to SmSoxS1, we have also identified an additional six Sox genes in schistosomes, two Sox B, one SoxC, and three Sox genes that may establish a flatworm-specific class of Sox genes with planarians. These data identify novel Sox genes in schistosomes to expand the potential functional roles for Sox2 and may provide interesting insights into early multicellular development of flatworms.

RESUMEN

The precise control of neural crest stem cell delamination, migration and differentiation ensures proper craniofacial and head development. Sox2 shapes the ontogeny of the cranial neural crest to ensure precision of the cell flow in the developing head. Here, we review how Sox2 orchestrates signals that control these complex developmental processes.

Asunto(s)

RESUMEN

Hemichordate enteropneust worms regenerate extensively in a manner that resembles the regeneration for which planaria and hydra are well known. Although hemichordates are often classified as an extant phylogenetic group that may hold ancestral deuterostome body plans at the base of the deuterostome evolutionary line leading to chordates, mammals, and humans, extensive regeneration is not known in any of these more advanced groups. Here we investigated whether hemichordates deploy functional homologs of canonical Yamanaka stem cell reprogramming factors, Oct4, Sox2, Nanog, and Klf4, as they regenerate. These reprogramming factors are not expressed during regeneration of limbs, fins, eyes or other structures that represent the best examples of regeneration in chordates. We first examined Ptychodera flava EST libraries and identified Pf-Pou3, Pf-SoxB1, Pf-Msxlx, and Pf-Klf1/2/4 as most closely related to the Yamanaka factors, respectively. In situ hybridization analyses revealed that all these homologs are expressed in a distinct manner during head regeneration. Furthermore, Pf-Pou3 partially rescued the loss of endogenous Oct4 in mouse embryonic stem cells in maintaining the pluripotency gene expression program. Based on these results, we propose that hemichordates may have co-opted these reprogramming factors for their extensive regeneration or that chordates may have lost the ability to mobilize these factors in response to damage. The robustness of these pluripotency gene circuits in the inner cell mass and in formation of induced pluripotent stem cells from mammalian somatic cells shows that these programs are intact in humans and other mammals and that these circuits may respond to as yet unknown gene regulatory signals, mobilizing full regeneration in hemichordates.

RESUMEN

Nervous system development has been intensely studied in insects (especially Drosophila melanogaster), providing detailed insights into the genetic regulatory network governing the formation and maintenance of the neural stem cells (neuroblasts) and the differentiation of their progeny. Despite notable advances over the last two decades, neurogenesis in other arthropod groups remains by comparison less well understood, hampering finer resolution of evolutionary cell type transformations and changes in the genetic regulatory network in some branches of the arthropod tree of life. Although the neurogenic cellular machinery in malacostracan crustaceans is well described morphologically, its genetic molecular characterization is pending. To address this, we established an in situ hybridization protocol for the crayfish Procambarus virginalis and studied embryonic expression patterns of a suite of key genes, encompassing three SoxB group transcription factors, two achaete-scute homologs, a Snail family member, the differentiation determinants Prospero and Brain tumor, and the neuron marker Elav. We document cell type expression patterns with notable similarities to insects and branchiopod crustaceans, lending further support to the homology of hexapod-crustacean neuroblasts and their cell lineages. Remarkably, in the crayfish head region, cell emigration from the neuroectoderm coupled with gene expression data points to a neuroblast-independent initial phase of brain neurogenesis. Further, SoxB group expression patterns suggest an involvement of Dichaete in segmentation, in concordance with insects. Our target gene set is a promising starting point for further embryonic studies, as well as for the molecular genetic characterization of subregions and cell types in the neurogenic systems in the adult crayfish brain.

Asunto(s)

RESUMEN

The arthropod compound eye represents one of two major eye types in the animal kingdom and has served as an essential experimental paradigm for defining fundamental mechanisms underlying sensory organ formation, function, and maintenance. One of the most distinguishing features of the compound eye is the highly regular array of lens facets that define individual eye (ommatidial) units. These lens facets are produced by a deeply conserved quartet of cuticle-secreting cells, called Semper cells (SCs). Also widely known as cone cells, SCs were originally identified for their secretion of the dioptric system, i.e. the corneal lens and underlying crystalline cones. Additionally, SCs are now known to execute a diversity of patterning and glial functions in compound eye development and maintenance. Here, we present an integrated account of our current knowledge of SC multifunctionality in the Drosophila compound eye, highlighting emerging gene regulatory modules that may drive the diverse roles for these cells. Drawing comparisons with other deeply conserved retinal glia in the vertebrate single lens eye, this discussion speaks to glial cell origins and opens new avenues for understanding sensory system support programs.

Asunto(s)

RESUMEN

Anti-Sry-like high mobility group box (SOX) 1 antibodies (abs) are partly characterized onconeural autoantibodies (autoabs) due to their correlation with neoplastic diseases. Anti-SOX1 abs are associated with various clinical manifestations, including Lambert-Eaton myasthenic syndrome (LEMS) and paraneoplastic cerebellar degeneration (PCD). However, the clinical characteristics of patients with anti-SOX1 abs have not been described in detail. This review systematically explores the reported patients with anti-SOX1 abs and analyzes these cases for demographic characteristics, clinical features, coexisting neuronal autoabs, neuroimaging findings, treatment, and clinical outcomes. In addition, considering that PCD is the most common paraneoplastic neurological syndrome and that the association between PCD and anti-SOX1 abs remains unclear, we focus on the presence of autoabs in relation to PCD and associated tumors. PCD-associated autoabs include various intracellular autoabs (e.g., anti-Hu, anti-Yo, anti-Ri, and anti-SOX1) and cell-surface autoabs (anti-P/Q-type voltage-gated calcium channel). Commonly involved tumors in PCD are small-cell lung cancer (SCLC), gynecological, and breast tumors. LEMS is the most common clinical symptom in patients with anti-SOX1 abs, followed by PCD, and multiple neuronal autoabs coexist in 47.1% of these patients. SCLC is still the predominant tumor in patients with anti-SOX1 abs, while non-SCLC is uncommon. No consistent imaging feature is found in patients with anti-SOX1 abs, and there is no consensus on either the therapy choice or therapeutic efficacy. In conclusion, the presence of anti-SOX1 abs alone is a potential predictor of an uncommon paraneoplastic neurological disorder, usually occurring in the setting of LEMS, PCD, and SCLC. The detection of anti-SOX1 abs contributes to an early diagnosis of underlying tumors, given the diversity of clinical symptoms and the absence of characteristic neuroimaging features.

RESUMEN

Sulfur-oxidizing bacterial diversity at the surface of cattle manure was characterized throughout the composting process using a sulfur oxidation gene (soxB) clone library approach. In the mesophilic phase, clones related to the genera Hydrogenophaga and Hydrogenophilus were characteristically detected. In the thermophilic phase, clones related to the genera Hydrogenophaga and Thiohalobacter were predominant. In the cooling phase, the predominant soxB sequences were related to the genus Pseudaminobacter and a new sulfur-oxidizing bacterium belonging to the class Alphaproteobacteria. The present study showed changes in the community composition of sulfur-oxidizing bacteria at the surface of compost throughout the composting process.

Asunto(s)

RESUMEN

Specification of the main axes of polarity of the embryo is an essential process during embryonic development. In many species, this process is achieved by the localization of maternal factors into discrete regions of the egg. However, in other animals, like in amniotes and in echinoderms, the considerable plasticity of the early blastomeres seems to preclude the existence of maternal determinants and the mechanisms by which the radial symmetry of the egg is broken remain largely enigmatic. In this chapter, we review recent progress on the identification of maternal components involved in symmetry breaking and dorsal-ventral (D/V) axis formation of the sea urchin embryo. We will first review some key experiments on D/V axis formation from classical embryologists that provided evidence for a weak maternal D/V prepattern. We will then detail more recent molecular analyses that established the critical role played by Nodal signaling in allocating cell fates along the secondary axis and led to the discovery that maternal transcription factors such as the Sry-related HMG box B1 (SoxB1), the Octamer binding factor1/2 (Oct1/2), the T-cell factor/Lymphoid enhancer-binding factor (TCF/LEF) and the Erythroblastosis virus E26 Oncogene Homolog (ETS) domain transcriptional repressor Translocation-Ets-Leukemia virus protein (Yan/Tel) as well as maternal signaling molecules like Univin are essential for the initiation of nodal expression. Finally, we will describe recent advances that uncovered a role in symmetry breaking and dorsal-ventral axis orientation for the transforming growth factor beta (TGF-beta)-like factor Panda, which appears to be both necessary and sufficient for D/V axis orientation. Therefore, even in the highly regulative sea urchin embryo, the activity of localized maternal factors provides the embryo with a blueprint of the D/V axis.

Asunto(s)

RESUMEN

In early vertebrate embryos, the dorsal ectoderm is induced by the axial mesendoderm to form the neural plate, which is given competence to form neural cells by soxB1 genes. Subsequently, neurogenesis proceeds in proneural clusters that are generated by a gene network involving proneural genes and Notch signaling. However, what occurs between early neural induction and the later initiation of neurogenesis has not been fully revealed. In the present study, we demonstrated that during gastrulation, the expression of the Oct4-related PouV gene pou5f3 (also called pou2), which is widely observed at earlier stages, was rapidly localized to an array of isolated spotted domains, each of which coincided with individual proneural clusters. Two-color in situ hybridization confirmed that each pou5f3-expressing domain included a proneural cluster. Further analysis demonstrated that anterior pou5f3 domains straddled the boundaries between rhombomere 1 (r1) and r2, whereas posterior domains were included in r4. The effects of forced expression of an inducible negative dominant-interfering pou5f3 gene suggested that pou5f3 activated early proneural genes, such as neurog1 and ebf2, and also soxB1, but repressed the late proneural genes atoh1a and ascl1b. Furthermore, pou5f3 was considered to repress her4.1, a Notch-dependent Hairy/E(spl) gene involved in lateral inhibition in proneural clusters. These results suggest that pou5f3 promotes early neurogenesis in proneural clusters, but negatively regulates later neurogenesis. Suppression of pou5f3 also altered the expression of other her genes, including her3, her5, and her9, further supporting a role for pou5f3 in neurogenesis. In vitro reporter assays in P19 cells showed that pou5f3 was repressed by neurog1, but activated by Notch signaling. These findings together demonstrate the importance of the pou5f3-mediated gene regulatory network in neural development in vertebrate embryos.

Asunto(s)

RESUMEN

Despite the unprecedented gene editing capability of CRISPR-Cas9-mediated targeted knock-in, the efficiency and precision of this technology still require further optimization, particularly for multicellular model organisms, such as the zebrafish (Danio rerio). Our study demonstrated that an ∼200 base-pair sequence encoding a composite tag can be efficiently "knocked-in" into the zebrafish genome using a combination of the CRISPR-Cas9 ribonucleoprotein complex and a long single-stranded DNA (lssDNA) as a donor template. Here, we targeted the sox3, sox11a, and pax6a genes to evaluate the knock-in efficiency of lssDNA donors with different structures in somatic cells of injected embryos and for their germline transmission. The structures and sequence characteristics of the lssDNA donor templates were found to be crucial to achieve a high rate of precise and heritable knock-ins. The following were our key findings: (1) lssDNA donor strand selection is important; however, strand preference and its dependency appear to vary among the target loci or their sequences. (2) The length of the 3' homology arm of the lssDNA donor affects knock-in efficiency in a site-specific manner; particularly, a shorter 50-nt arm length leads to a higher knock-in efficiency than a longer 300-nt arm for the sox3 and pax6a knock-ins. (3) Some DNA sequence characteristics of the knock-in donors and the distance between the CRISPR-Cas9 cleavage site and the tag insertion site appear to adversely affect the repair process, resulting in imprecise editing. By implementing the proposed method, we successfully obtained precisely edited sox3, sox11a, and pax6a knock-in alleles that contained a composite tag composed of FLAGx3 (or PAx3), Bio tag, and HiBiT tag (or His tag) with moderate to high germline transmission rates as high as 21%. Furthermore, the knock-in allele-specific quantitative polymerase chain reaction (qPCR) for both the 5' and 3' junctions indicated that knock-in allele frequencies were higher at the 3' side of the lssDNAs, suggesting that the lssDNA-templated knock-in was mediated by unidirectional single-strand template repair (SSTR) in zebrafish embryos.

RESUMEN

Sox transcription factors play many diverse roles during development, including regulating stem cell states, directing differentiation, and influencing the local chromatin landscape. Of the twenty vertebrate Sox factors, several play critical roles in the development the neural crest, a key vertebrate innovation, and the subsequent formation of neural crest-derived structures, including the craniofacial complex. Herein, we review the specific roles for individual Sox factors during neural crest cell formation and discuss how some factors may have been essential for the evolution of the neural crest. Additionally, we describe how Sox factors direct neural crest cell differentiation into diverse lineages such as melanocytes, glia, and cartilage and detail their involvement in the development of specific craniofacial structures. Finally, we highlight several SOXopathies associated with craniofacial phenotypes.

RESUMEN

In the developing Drosophila central nervous system (CNS), neural progenitor (neuroblast [NB]) selection is gated by lateral inhibition, controlled by Notch signaling and proneural genes. However, proneural mutants still generate many NBs, indicating the existence of additional proneural genes. Moreover, recent studies reveal involvement of key epithelial-mesenchymal transition (EMT) genes in NB selection, but the regulatory interplay between Notch signaling and the EMT machinery is unclear. We find that SoxNeuro (SoxB family) and worniu (Snail family) are integrated with the Notch pathway, and constitute the missing proneural genes. Notch signaling, the proneural, SoxNeuro, and worniu genes regulate key EMT genes to orchestrate the NB selection process. Hence, we uncover an expanded lateral inhibition network for NB selection and demonstrate its link to key players in the EMT machinery. The evolutionary conservation of the genes involved suggests that the Notch-SoxB-Snail-EMT network may control neural progenitor selection in many other systems.

Asunto(s)

RESUMEN

OBJECTIVES: Cancer stem cells are involved in radioresistant cancers. Transcription factors Sry-related HMG box (SOX2) and octamer binding transcription factor 4 (OCT4) can confer pluripotent cell characteristics and self-renewal ability and are involved in carcinogenesis, metastasis, tumor recurrence, and resistance to therapy. Apoptosis, DNA repair, and telomerase factors also contribute to radioresistance. We sought to identify the role of SOX2 and OCT4 as cancer stem cell markers and their effects on apoptosis (via caspase 3), DNA repair (Chk1) and telomerase (hTERT) in conferring resistance to radiotherapy. METHODS: We conducted a case-control study of 40 patients with stage IIIB cervical squamous cell carcinoma who completed radiation therapy at Cipto Mangunkusumo Hospital, Jakarta, Indonesia. The patients were classified according to their treatment response as having exhibited a complete or incomplete response. Clinical follow-up and Pap smears were performed between six and 12 months after therapy for those with a good initial response to determine the final response to therapy. Immunohistochemistry was used to analyze SOX2, OCT4, caspase-3, Chk1, and hTERT expression in paraffin sections of the initial biopsy. RESULTS: Strong expression of SOX2 (p = 0.011, p = 0.001) and OCT4 (p < 0.001, p < 0.001) was significantly associated with both an incomplete initial and final therapy response, respectively. Multivariate analysis showed that SOX2 and OCT4 expression levels were the strongest markers of an incomplete response to radiotherapy (odds ratio (OR) = 5.12, p = 0.034, and OR = 17.03, p = 0.004, respectively). CONCLUSIONS: Strong expression of SOX2 and OCT4 may be a good indicator of incomplete radiotherapy outcome in patients with stage IIIB cervical cancer.