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. 2025 Jul 2;24:152. doi: 10.1186/s12934-025-02777-y

Novel function of ribosomal protein RPL14B: regulation of CdSe quantum dots biosynthesis in living Saccharomyces cerevisiae cells

Jiye Liu 1, Yong Li 1, Jiawei Tu 2, Daiwen Pang 3, Lipeng Zhong 1,4,✉, Zhixiong Xie 1,✉
PMCID: PMC12220401  PMID: 40604988

Abstract

Biosynthesis of CdSe quantum dots is the process of converting metal ions into semiconductor nanomaterials. Studies have shown that CdSe quantum dots synthesized by Saccharomyces cerevisiae are rich in ribosomal proteins, but the role of ribosomal proteins in the synthesis of CdSe quantum dots remains unclear. In this paper, ribosomal proteins enriched during the synthesis of CdSe quantum dots by S. cerevisiae were screened, and their effects on the synthesis of quantum dots were detected by gene knockout and over-expression. The results reveal that ribosomal protein RPL14B is involved in the synthesis of quantum dots. RPL14B binds cadmium ions during the nucleation of CdSe quantum dots and acts as a template, ultimately regulating the particle size of CdSe quantum dots by change the incubation time of CdCl2. In summary, this study elucidates the mechanism of ribosomal protein RPL14B regulation of CdSe quantum dot biosynthesis, laying a foundation for the precise regulation of CdSe quantum dot synthesis.

Keywords: Ribosomal proteins, S. cerevisiae, Biosynthesis, Quantum dots, CdSe

Background

Quantum dots (QDs) have been widely used in recent years due to their unique photochemical and photophysical properties [1, 2]. For example, they can be used for in vivo imaging, diagnostics, ion detection, electro-optical devices, and chiral catalysis [3, 4]. Biological systems have received a lot of attention due to their environmental protection and energy saving features. In addition, many biosynthetic quantum dots have been applied in various fields [5, 6]. At present, quantum dots have been synthesized in Escherichia coli, S. cerevisiae and so on [7-9]. However, the synthetic mechanisms that produce quantum dots in living organisms have not been fully elucidated. Therefore, it is of great significance to study these mechanisms for regulating the synthesis process of quantum dots.

Our research group has demonstrated the synthesis of CdSe quantum dots in S. cerevisiae by coupling unrelated intracellular biochemical reactions [10-12]. Further studies have found that some proteins are encapsulated in CdSe quantum dots synthesized in S. cerevisiae, and most of the proteins are Ribosomal proteins (RPs) and proteins related to energy metabolism. However, there is little research on whether these are involved in the synthesis of CdSe quantum dots, and their role in the synthesis of CdSe quantum dots.

Currently, in vitro protein/peptide-based biomimetic mineralization has been shown to be an effective and promising strategy for synthesizing inorganic/metal nanoparticles (NPs) [13, 14]. Studies have shown that bifunctional peptides can be used as templates for the synthesis of core-shell CdSe/ZnS nanocrystals [15]. We speculate that the ribosomal protein of S. cerevisiae may serve as a template for the synthesis of CdSe quantum dots. In this paper, ribosomal proteins enriched in CdSe quantum dots of S. cerevisiae were screened and their effects on the synthesis of quantum dots were detected by gene knockout and over-expression. The key ribosomal protein RPL14B related to the synthesis of CdSe quantum dots in S. cerevisiae was discovered and the mechanism of their regulation on the synthesis of quantum dots was studied. This not only helps us to deepen the understanding of the synthesis mechanism of nanomaterials of S. cerevisiae, but also provides a new strategy for regulating the biosynthesis of nanomaterials.

Results

Protein identification wrapped on the surface of CdSe quantum dots

The CdSe quantum dots synthesized by S. cerevisiae were purified and identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total of 1169 proteins were detected, including those related to energy metabolism and 79 ribosomal proteins (Fig. 1). Proteins related to energy metabolism provide energy in the Se-rich stage and crystal formation stage of CdSe quantum dot synthesis [12]. However, whether ribosomal proteins participate in the synthesis of CdSe quantum dots by S. cerevisiae and what functions they can play have not been thoroughly studied. Among the ribosomal proteins detected by LC-MS/MS, it is likely that some of them are just non-characteristic wrapped on the surface of CdSe quantum dots and do not play a role in the formation of quantum dots, while some may play a direct role. Next, by screening the ability of ribosomal protein deficient strains to synthesize CdSe quantum dots, the ribosomal proteins involved in the synthesis of CdSe quantum dots were selected for further study.

Fig. 1.

Fig. 1

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Protein analysis wrapped on the surface of CdSe quantum dots. CdSe quantum dots were extracted from cells by cell wall breaking, ultrafiltration, gel electrophoresis and dialysis. The purified CdSe quantum dots were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS)

Bioinformatics analysis of gene expression during the synthesis of CdSe quantum Dots by S. cerevisiae

The gene expression data of S. cerevisiae were obtained in the Se rich stage (compared with the selenium and no selenium groups) and crystal formation stage (compared with the selenium and cadmium groups) of CdSe quantum dot synthesis. Gene Ontology (GO) is a database established by the Gene Ontology Consortium that can be used to analyze the genes of an organism and the functional properties of gene products. GO analysis of the up regulated gene in the selenium rich phase of CdSe synthesis by S. cerevisiae is shown in Fig. 2A. The analysis results show that after adding Na2SeO3 to S. cerevisiae, The up regulated genes are part of the meiotic cell cycle and the meiotic cell cycle process, as well as spore formation and cell wall assembly.

Fig. 2.

Fig. 2

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Enrichment of signaling pathway for S.cerevisiae synthesis of CdSe quantum dots. (A) Up regulated gene GO enrichment during the selenium rich phase of CdSe quantum dot synthesis; (B) KEGG pathway enrichment of up regulated gene during the selenium rich phase of CdSe quantum dot synthesis; (C) Up regulated gene GO enrichment during the formation stage of CdSe quantum dot synthetic crystals; (D) KEGG pathway enrichment of up regulated gene during the formation of CdSe quantum dot synthetic crystals

In the control group without selenium, the BY4742 strain was cultured at 30℃ without adding Na2SeO3. In addition to selenium, strain BY4742 was cultured at 30℃ and Na2SeO3 was added. Yeast total RNA was extracted from the selenium free group and the selenium supplemented group, and cDNA was prepared by reverse transcription, and then gene expression level was determined by expression profile chip hybridization. The obtained up regulated gene data were analyzed for GO enrichment. The smaller the P value, the more significant the difference. In order to study which pathways might be involved in the selenium-enriched phase of CdSe synthesis by S. cerevisiae, KEGG analysis was performed on the up regulated genes at this stage, and the results were shown in Fig. 2B. The analysis results showed that up regulated genes involved a total of 20 pathways, among which Meiosis related genes had the largest number of up regulations and the most significant differences. Secondly, there were significant differences in Glycerolipid metabolism and Basal transcription factors among groups.

KEGG enrichment analysis was performed on the data of the control group and the selenium group obtained by gene expression microarray technology. The smaller the P value, the more significant the difference was. The GO analysis of the crystal formation stage of CdSe quantum dots synthesized by S. cerevisiae is shown in Fig. 2C. The results show that many genes are up regulated in the formation process of quantum dots with the addition of CdCl2 on the basis of Se rich S. cerevisiae compared to the Se rich group with only Na2SeO3 added. These genes are part of cytoplasmic translation, ribosome biogenesis, ribosome small subunit biogenesis, In addition, ribosome assembly, rRNA metabolism, ribosome large subunit biosynthesis and other processes. These results suggest that ribosomal proteins are involved in the crystal formation phase of CdSe quantum dots synthesis by S. cerevisiae.

KEGG analysis was performed on up regulated genes in crystal formation stage of CdSe quantum dots synthesized by S. cerevisiae, and the results were shown in Fig. 2D. When CdCl2 was added to Se rich yeast, the number of up regulation was the largest, and ribosome protein was the largest difference between groups, followed by RNA polymerase.

KEGG enrichment analysis was performed on gene data obtained by gene expression microarray technology in selenium and cadmium free group (control group) and selenium and cadmium plus group. The smaller the P value, the more significant the difference. According to the results of the above GO analysis and KEGG analysis, in the two important stages of the synthesis of CdSe quantum dot, the stage of selenium enrichment and the stage of crystal formation, the gene encoding ribosome protein was not significantly up regulated in the stage of selenium enrichment, but was up regulated in the stage of crystal formation. These results suggest that S. cerevisiae regulates the expression of ribosomal protein genes during the formation of CdSe quantum dots to meet the demand for ribosomal proteins synthesized by CdSe quantum dots.

There are 35 ribosomal proteins identified in this study. Some studies have also identified proteins wrapped on the surface of CdSe quantum dots [12]. Among the 35 identified ribosomal proteins, 23 strains with protein deletion whose genes could be knocked out were selected for study Table 1, among which 8 strains with ribosomal protein deletion in 60 S and 15 strains with ribosomal protein deletion in 40 S. The ability of the 23 ribosomal protein deficient strains to synthesize CdSe quantum dots was screened. The experimental results showed that three ribosomal protein deletion strains (Δrps22a, Δrpl14b, Δrpl20a) had significantly reduced ability to synthesize CdSe quantum dots compared with the wild type (WT), and one ribosomal protein deletion strain (Δrps11b) had unstable ability to synthesize CdSe quantum dots (results not shown). Proteins can be connected within or between proteins through hydrophobic interactions dominated by non polar amino acids to form a large number of micro cavities to control and limit the growth of quantum dots, thus acting as a template [16]. Among the screened ribosomal proteins, RPL14B contained 49.28% of non polar amino acids, which was higher than that of RPS22A (41.54%) and RPL20A (40.11%). Therefore, RPL14B was selected as the research object. The mechanism of CdSe quantum dots was studied in detail.

Table 1.

Ribosomal protein deficient strains

Subunit Deletion strain
60 S ribosomal protein Δrpl14b, rpl20a, rpl11b, rpl13a, rpl4a, rpl8b, rpl7a, rpl9a
40 S ribosomal protein Δrps22a, rps11b, rps16b, rps18a, rps23a, rps1a, rps4b, rps6b, rps7b, rps7a, rps10b, rps0a, rps8a, rps9a, rps12
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rpl14b affects the fluorescence intensity of biosynthesized CdSe quantum dots

And then the strain, was constructed by genetic techniques to realize the over expression of the rpl14b. To confirm the speculation that rpl14b is involved in the biosynthesis of CdSe QDs, we measured the fluorescence intensity of S. cerevisiae strains, namely WT, the rpl14b deletion strain (Δrpl14b), and the rpl14b over expressing strain (PGAL1-RPL14B). The fluorescence intensity of Δrpl14b was half that of the WT, whereas that of the PGAL1-RPL14B was increased 2–3 folds versus WT(Fig. 3A). Images following UV light irradiation (Fig. 3B) and fluorescence microscopy images (Fig. 3C) of WT cells, Δrpl14b cells, and PGAL1-RPL14B cells after the biosynthesis of CdSe QDs corresponded with the results of the fluorescence intensity analysis. Taken together, the above results indicated that the ribosomal protein rpl14b participated in the synthesis of CdSe QDs in S. cerevisiae.

Fig. 3.

Fig. 3

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Fluorescence properties of CdSe QDs in different strains. (A) Intracellular fluorescence intensities (n = 3. **P < 0.01), (B) UV light irradiation and (C) Fluorescence microscopy images (exposure time, 100 ms; scale bar, 5 μm) of WT,Δ rpl14b, and PGAL1-RPL14B cells after the biosynthesis of CdSe QDs

Considering that the cell growth might be affected the synthesis of QDs, the growth curve of the WT strain, the Δrpl14b strain, and the PGAL1-RPL14B strain were measured. The results displayed that the deletion of rpl14b had no obvious growth defect, which was consistent with the findings in previous reports, implying that the rpl14b affected the synthesis of CdSe QDs not by through affecting its growth (data not shown).

rpl14b is involved in the formation of CdSe quantum dot crystals

In the study of microbial metabolism, synthesis and other mechanisms, gene transcription level can be used to reflect whether genes participate in the biological process under study. In order to study the function of ribosomal proteins in the synthesis of CdSe quantum dots in S. cerevisiae, and further reveal the mechanism of ribosomal proteins regulating the synthesis of quantum dots, rpl14b expression levels at different stages of CdSe quantum dot biosynthesis were detected (Fig. 4). There are two main stages in the synthesis of CdSe quantum dots by S. cerevisiae, namely Se enrichment and CdSe quantum dot crystal formation stage. The gene expression level of S. cerevisiae during the Se rich phase of CdSe quantum dot synthesis showed that rpl14b was not up regulated. Detection of gene expression levels during the formation stage of synthetic CdSe quantum dot crystals in S. cerevisiae showed that rpl14b expression was up regulated by a factor of 2.4. The fluorescence intensity of Δrpl14b was half reduced compared to the WT. The expression levels of rpl14b in different stages of the biosynthesis of CdSe were determined. The results revealed that the transcription levels of the rpl14b in the selenized yeast cells were similar to those in normal yeast cells. Furthermore, rpl14b was detected during the addition of CdCl2 to selenium rich yeast. An interesting finding was that the rpl14b was significantly up regulated during the addition of CdCl2 to selenium rich yeast, which indicated that rpl14b played a vital role in the formation of CdSe QDs.

Fig. 4.

Fig. 4

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qRT-PCR was used to detect the expression level of rpl14b in Na2SeO3 group, compared with that without adding Na2SeO3 (Control). The gene expression of selenium-rich yeast + CdCl2 was compared with that of selenium-enriched yeast without CdCl2 (Control)

A short peptide derived from the RPL14B specifically binds to cadmium ions

In previous studies, cysteine was often used as a ligand to synthesize CdSe quantum dots in vitro, so we guessed that small peptide containing Cys of RPL14B played a role in the synthesis of CdSe quantum dots. In order to explore the function of RPL14B, we synthesized hexapeptide (89GVCEKW94) from RPL14B and tested the interaction force of the Cd2+. The Isothermal titration calorimetry (ITC) responses recorded during titration of the hexapeptide with Cd2+ (Fig. 5). ITC data showed that the Kd was 6.43 ± 0.0749 µM, which provided evidence for binding of peptides to Cd2+. Isothermal titration curve and fitting curve recorded by Cd2+ titrated point mutant hexapeptide (GVSEKW). ITC data showed that the Kd value of GVSEKW sequence was 2.23 ± 0.867 mM, indicating that the GVSEKW show very weak affinity to Cd2+, the Kd value was only at the mM leve.

Fig. 5.

Fig. 5

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Isothermal titration calorimetry (ITC) of the binding of the Cd2+ to hexapeptide

Cys site on RPL14B converted to SeCys

In order to further study the role of RPL14B in the biosynthesis of CdSe quantum dots, the Se rich BL21/pET26b-rpl14b strain was extracted and identified by LC-MS/MS. The results showed that the Cys site on RPL14B changed to SeCys during the process of selenium enrichment (Fig. 6).

Fig. 6.

Fig. 6

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LC-MS/MS diagram of RPL4B after selenium enrichment

PGAL1-RPL14B synthesized CdSe QDs in S. cerevisiae

In order to verify the properties of the CdSe QDs synthesized by the PGAL1-RPL14B strain, they were characterized by transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), which showed that the purified CdSe QDs from PGAL1-RPL14B were of uniform sizes (3.0 ± 0.3 nm, mean ± SD, n = 200) (Fig. 7A) and that the QDs exhibited planar faces of (1Inline graphic1) (d = 0.21 nm) and (201) (d = 0.18 nm) (Fig. 7B). EDX characterization results showed that the elements in the QDs from PGAL1-RPL14B were Cd and Se, and the molar ratio was 1:1.29 (Fig. 7C), which indicated that the nanoparticles biosynthesized using the PGAL1-RPL14B cells were indeed CdSe QDs. The parameters of the CdSe QDs were consistent with previously reported. Photoluminescence(PL) Spectroscopy emission peak of CdSe QDs was at 528 nm (Fig. 7D).

Fig. 7.

Fig. 7

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Characterization of CdSe QDs isolated from the PGAL1- RPL14B cells. (A) TEM image, (B) HRTEM image, (C) EDX spectrum and (D) PL emission spectra

RPL14B manipulates the synthesis of CdSe quantum dots in S. cerevisiae

In addition, fluorescence microscopy images showed that the color of fluorescence from PGAL1-RPL14B cells shifted from yellow to red by changing the incubation time in CdCl2 from 24 h to 40 h (Fig. 8). These results suggest that changing the incubation time in CdCl2 may provide ways for the purposeful production of QDs with the desired fluorescence characteristics using the engineered PGAL1-RPL14B strain.

Fig. 8.

Fig. 8

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Fluorescence microscopy images of PGAL1-RPL14B cells cultured in YPGal medium according to the designed route; 24 h for yellow (exposure time, 100 ms; scale bar, 5 μm); 40 h for red (exposure time, 800 ms; scale bar, 5 μm)

Discussion

RPL14B is a component of the large subunit of the ribosome, which is involved in protein synthesis. The stage of S. cerevisiae synthesis of CdSe QDs can be divided into a selenium enrichment stage and a crystal formation stage [17]. Our experimental results show that the ribosomal protein RPL14B participates in the crystal formation stage, but has no obvious function in the selenium enrichment stage. In order to improve the system of quasi-biosynthesis, the role of ribosomal protein RPL14B in quasi biological system was studied. The results of in vitro experiments showed that RPL14B contains a functional region that binds to Cd2+ and can be used as a template to synthesize CdSe QDs. In yeast, the RPL14B plays a key role in the formation of QDs. The proportion of non-polar amino acids in RPL14B was 49.28%, which was higher than that in RPS22A (41.54%) and RPL20A (40.11%). It may be through the hydrophobic interaction of non-polar amino acids within or between proteins, which can form numerous of micro-cavities to control and limit the growth of quantum dots, thus acting as a template.

Conclusions and outlook

Quasi-biological system are powerful tools for synthesizing QDs [18]. In this work, CdSe QDs were self-assembled in S. cerevisiae. And it was demonstrated for the first time that the ribosomal protein RPL14B participated in the process. And a reasonable mechanism was proposed, ribosomal protein RPL14B can be used as a template in the synthesis, because it contains Cd2+-binding sequence (Fig. 9). It is found that the regulation of the synthesis of CdSe quantum dots by S. cerevisiae can be achieved through the enrichment of ribosomal proteins, and the fluorescent color of the CdSe quantum dots synthesized by the engineered strain (PGAL1-RPL14B) is controllable, and the storage stability is good.

Fig. 9.

Fig. 9

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Mechanism of action of ribosomal protein RPL14B in CdSe quantum dot biosynthesis. Ribosomal protein RPL14B as a template contains peptides that can simultaneously bind Cd2+ and participate in the synthesis of CdSe quantum dots in S. cerevisiae cells through selenocysteine

The above results show that we have analyzed the mechanism of ribosomal protein involved in the synthesis of CdSe quantum dots through in vivo and in vitro experiments, laying a foundation for improving the understanding of the mechanism of CdSe quantum dot synthesis by S. cerevisiae. This method of using template proteins to control the synthesis of quantum dots, offering new insights for biosynthesis and quasi-biosynthesis.

Materials and methods

Materials and strain growth conditions

The strains S. cerevisiae BY4742 (MATα his3-Δ1, leu2-Δ0lys2-Δ0 ura3-Δ0), PGAL1-RPL14B, and Δrpl14b were used in this study. The Δrpl14b and wild-type (WT) strains were obtained from the European S. cerevisiae Archive for Functional Analysis (Bad Homburg, Germany). The PGAL1-RPL14B strains were constructed from the S. cerevisiae BY4742 strain in this study. The identification of strains by PCR indicated that PGAL1-RPL14B strain was successfully constructed. Peptone and yeast extracts were purchased from BD (USA). Galactose was purchased from Amresco (USA). The other reagents used in this work were obtained from Sinopharm Chemical Reagent Co., (China). Cultures of yeast in YPGal medium were performed by shaking at 200 rpm at 30 °C.

Chip experiment and data analysis

Total RNA was extracted from the selenium-free and cadmium-free group (yeast cell BY4742 treated without Na2SeO3 and CdCl2), the selenium and cadmium-free group (yeast cell BY4742 treated with Na2SeO3 and without CdCl2) and the both selenium and cadmium group (yeast cell BY4742 treated with Na2SeO3 and CdCl2), respectively. cDNA was obtained by reverse transcription, and then gene expression level data was obtained by expression profile chip test. Perform bioinformatics analysis on gene expression data obtained from yeast cells through three different treatments in Gene Ontology (GO) (http://www.geneontology.org) and Kyoto Encyclopedia of Genes and Genomes KEGG (http://www.genome.jp/kegg)

Expression and purification of RPL14B

E. coli DH5α was used for vector construction of pET26b-rpl14b, and E. coli BL21 (DE3) was used to express the RPL14B. The rpl14b gene was cloned from the S. cerevisiae genome and inserted into pET26b. The resulting pET26b-rpl14b plasmid was then transformed into E. coli BL21 (DE3) which was cultured in 500 mL of LB broth at 37 °C and the expression of the soluble RPL14B was low temperature induced by the addition of 0.1 mM IPTG. The cells were collected by centrifugation, suspended in 15 mL of Soluble Binding buffer (20 mM Tris-HCl, 0.5 M NaCl, pH 7.9), sonicated and centrifuged. The RPL14B containing a His tag was obtained by purification using a His Tagged Protein Purification Kit (cw bio, China).

Isothermal titration calorimetry

Peptides (GVCEKW) were synthesized at Sangon Biotech Co., Ltd (China). According to literature reports the isothermal titration calorimetry (ITC) experiment was performed using Microcal VP-ITC (USA) [19, 20]. Before the experiment, the peptide and CdCl2 were dissolved in the same solvent (Tris-HCl, pH 7.7). The reaction cell (200µL) was the peptide solution and the injection syringe (70µL) was CdCl2 solution. In this experiment, the first droplet was set to 0.4µL, followed by 18 subsequent injections of 2µL.

RNA isolation and qRT-PCR

RNA isolation and qRT-PCR Total RNA of S. cerevisiae were treated by the hot phenol method [21, 22]. The PrimeScript RT reagent Kit with gDNA Eraser (TaKaRa, Japan) was used to reverse RNA to cDNA. Then, qPCR reactions for genes were performed by using the designed primers and triplicate PCRs in a qPCR machine (CFX96 RT-PCR detection system; Bio-Rad Technologies; Bio-rad, USA). The PCR cycling conditions experiments were performed as follows: denaturation at 95 °C for 30s, and quantitation repeat for 39 cycles (95 °C for 30s, 60 °C for 30s, 72 °C for 30s). Fluorescence intensity was measured at the end of each cycle. Experimental data was analyzed according to comparative threshold cycle (CT) method, act1 was used as a reference gene.

Purification of CdSe QDs

Purification of CdSe quantum dots synthesized by S. cerevisiae: Cells with a wet weight of 1 g CdSe quantum dots were weighed, suspended with a configured 3 mL lysis buffer (10 mM Tris-HCl pH 7.5, 0.2% SDS), and then transferred to a 1.5 mL cell breaking tube containing 0.5 g pickling glass beads. The cells were broken six times with the minibeadater 16 grinding bead crusher, each time for 1 min, and ice bath for 2 min. After crushing, the precipitation was removed by centrifuge at 4℃, the supernatant was collected, and the surfactant sodium dodecyl sulfate (SDS) with a final concentration of 0.2% was added. Then the supernatant was centrifuged with 100 KDa ultrafiltration tube at 4℃ with centrifugation parameters of 4000 g for 20 min. The quantum dot samples were further purified by gel electrophoresis and dialysis.

Fluorescence detection of CdSe QDs

For the CdSe quantum dots synthesized using yeast, yeast cell cultures were collected and washed at an OD600 of 6 (OD600 of 1 ≈ 1 × 107 cells). For CdSe quantum dots synthesized using the quasi-biological system, the solution was collected and centrifuged for further analysis. Fluorescence intensity was measured using a Fluorolog-3 spectrometer (HORIBA Jobin Yvon France), with an excitation wavelength of 400 nm, and a detection emission spectrum of 420–700 nm. Fluorescent images of cells were captured using the fluorescence inverted microscope namely Olympus 1 × 51 (Olympus, Japan).

Characterization of CdSe QDs

The purification of CdSe quantum dots in S. cerevisiae was carried out as previously described. The purified CdSe QDs were diluted to a suitable concentration, about 10 times, and then 3 µL of the sample was dropped onto ultrathin carbon-coated copper grids and dried for at least 3 h before characterization by transmission electron microscopy (TEM) and high-resolution TEM (HRTEM). The TEM images and HRTEM images were obtained using a JEM-1400plus, JEM-2100 (HR) microscope at 200 kV, respectively. EDX data were obtained using a JEM-2100 (HR) microscope equipped with a GENESIS XM2.

Synthesis of CdSe quantum dots controlled by PG-AL1-RPL14B in S. cerevisiae

The synthesis method used by S. cerevisiae for CdSe quantum dots is “time-space coupling strategy”, and the specific experimental steps are as follows [12]. Activated S. cerevisiae cells are transferred to fresh YPD or YPGal medium at 2% transfer amount, and cultured at 30℃ and 200 rpm until stable period (24 h). Na2SeO3 with a final concentration of 2.5 mM was added and cultured at 200 rpm at 30℃ for 24 h. The bacteria were collected by centrifugation, the supernatant was removed, and then re-suspended with fresh YPD or YPGal medium, and CdCl2 solution with a final concentration of 1 mM was added. Selenium-rich yeast cells were incubated with CdCl2 for 24 h and 40 h. After washing the cells twice with 1 mL 1×PBS, the cell solution of 1–2 µL was dropped on a slide, the slide was covered, and fluorescence images of the cells were taken with fluorescence microscope.

Acknowledgements

Not applicable.

Author contributions

Jiye Liu performed experiments, analyzed data, and wrote the manuscript. Yong Li and Jiawei Tu performed transcriptome. Lipeng Zhong performed experiments and edited the manuscript, Zhixiong Xie and Daiwen Pang directed overall research, and edited the manuscript.

Funding

This work is financially supported by the National Natural Science Foundation of China (31800028 and 31570090), the National Basic Research Program of China (973 Program) (2013CB933904).

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Footnotes

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Contributor Information

Lipeng Zhong, Email: zhongliborn@whu.edu.cn.

Zhixiong Xie, Email: zxxie@whu.edu.cn.

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Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Data Availability Statement

No datasets were generated or analysed during the current study.

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