Biology subjects

Jansova, D.

Publications and source records attributed to Jansova, D..

3 recordsLinked to original sources

bioRxiv2024

Absence of CDK12 in oocyte leads to female infertility

Transcriptional activity and gene expression are essential for the development of a mature, meiotically competent oocyte. We have found that the absence of cyclin-dependent kinase 12 (CDK12) in oocytes leads to complete female sterility, as there are no fully developed oocytes able to accomplish meiosis I in the ovaries. Mechanistically, CDK12 in growing oocytes controls POLII activity and maintenance of the physiological maternal transcriptome, which negatively affects protein synthesis that promotes further oocyte growth. In addition, disruption of oocyte development disrupts folliculogenesis, resulting in a premature failure phenotype without terminal folliculogenesis and ovulation. In summary, we have characterized a single master regulator of the oocyte transcriptional program and gene expression that is essential for oocyte growth and female fertility. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=113 HEIGHT=200 SRC="FIGDIR/small/622910v1_ufig1.gif" ALT="Figure 1"> View larger version (16K): org.highwire.dtl.DTLVardef@179b286org.highwire.dtl.DTLVardef@b7a847org.highwire.dtl.DTLVardef@1890a35org.highwire.dtl.DTLVardef@1fd2798_HPS_FORMAT_FIGEXP M_FIG C_FIG

developmental biology↗

bioRxiv2024

Pancreatic cancer cells exchange ribosomes through tunneling nanotubes

O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=112 SRC="FIGDIR/small/597772v3_ufig1.gif" ALT="Figure 1"> View larger version (19K): org.highwire.dtl.DTLVardef@1f66716org.highwire.dtl.DTLVardef@1ea14eeorg.highwire.dtl.DTLVardef@1044da2org.highwire.dtl.DTLVardef@184d8a3_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstractC_FLOATNO C_FIG Key pointsO_LIpancreatic tumour cell lines and cells from patient biopsies form tunnelling nanotubes in 2D culture C_LIO_LIformation of tunnelling nanotubes is promoted by gemcitabine C_LIO_LIpolyadenylated mRNAs, ribosomal components and assembled ribosomes are present in tunnelling nanotubes C_LIO_LIribosomes and their components are transferred via nanotubes to acceptor cells C_LIO_LIsilencing of ribosomal proteins S6 and L24 reduces the number of assembled ribosomes C_LIO_LIglobal protein synthesis and number of ribosomes in pancreatic cancer cells with silenced ribosomal proteins increases when co-cultured with translationally unimpaired cells C_LI BackgroundPancreatic ductal adenocarcinoma (PDAC) is considered as one of the deadliest types of cancer. Tunnelling nanotubes (TNTs) are thin, membranous, intercellular communication structures observed in normal and cancer cells, where they mediate the exchange of intracellular material and promote cell fitness, cancer spread and treatment resistance. ResultsPDAC cells increase the formation of TNTs upon exposure to gemcitabine. In the PANC-1 cell line and in tumour explants from patients, we observe polyadenylated mRNA, 5.8S rRNA, ribosomal proteins and assembled 80S ribosomes within the TNTs. Using HaloTag-labelled small ribosomal subunit component RPS9 we demonstrate the transport of ribosomes via TNTs into acceptor cells. Downregulation of ribosomal proteins S6 and L24 decreases the number of assembled ribosomes and the global protein translation in PDAC cells, while a co-culture with translationally unimpaired cells partially restores protein synthesis in cells with impaired protein translation. ConclusionsPDAC cells can exchange components of the protein translation machinery and mRNA. The intercellular transfer of these components causes a partial restoration of protein translation in cells with impaired protein synthesis, which may contribute to the resilience of pancreatic cancer cells, highlighting the potential of targeting TNT dynamics as a therapeutic approach for PDAC.

cancer biology↗

bioRxiv2020

p38-MAPK mediated rRNA processing and translation regulation enables PrE differentiation during mouse blastocyst maturation.

Backgroundp38-MAPKs are stress-activated kinases necessary for placental development and nutrient and oxygen transfer during murine post-implantation development. In preimplantation development, p38-MAPK activity is required for blastocyst formation. Additionally, we have previously reported its role in regulating specification of inner cell mass (ICM) towards primitive endoderm (PrE), although a comprehensive mechanistic understanding is currently limited. Adopting live embryo imaging, proteomic and transcriptomic approaches, we report experimental data that directly address this deficit. ResultsChemical inhibition of p38-MAPK activity during blastocyst maturation causes impaired blastocyst cavity expansion, most evident between the third and tenth hours post inhibition onset. We identify an overlapping minimal early blastocyst maturation window of p38-MAPKi inhibition (p38-MAPKi) sensitivity, that is sufficient to impair PrE cell fate by the late blastocyst (E4.5) stage. Comparative proteomic analyses reveal substantial downregulation of ribosomal proteins, the mRNA transcripts of which are also significantly upregulated. Ontological analysis of the differentially expressed transcriptome during this developmental period reveals "translation" related gene transcripts as being most significantly, yet transiently, affected by p38-MAPKi. Moreover, combined assays consistently report concomitant reductions in de novo translation that are associated with accumulation of unprocessed rRNA precursors. Using a phosphoproteomic approach, {+/-} p38-MAPKi, we identified Mybpp1a, an rRNA transcription and processing regulator gene, as a potential p38-MAPK effector. We report that siRNA mediated clonal knockdown of Mybpp1a is associated with significantly diminished PrE contribution. Lastly, we show that defective PrE specification caused by p38-MAPKi (but not MEK/ERK signalling inhibition) can be partially rescued by activating the archetypal mTOR mediated translation regulatory pathway. ConclusionsActivated p38-MAPK controls blastocyst maturation in an early and distinctly transient developmental window by regulating gene functionalities related to translation, that creates a permissive environment for appropriate specification of ICM cell fate.

developmental biology↗