KPNA7, an oocyte- and embryo-specific karyopherin?subtype, is required for porcine embryo development

Abstract

Coordinated partitioning of intracellular cargoes between nuclear and cytoplasmic compartments is critical for cell survival and differentiation. The karyopherin α/β heterodimer functions to import cytoplasmic proteins that possess classical nuclear localisation signals into the nucleus. Seven karyopherinαsubtypes have been identified in mammals. The aim of this study was to determine the relative abundance of transcripts encoding seven karyopherinαsubtypes in porcine oocytes and embryos at discrete stages of cleavage development, and to determine the developmental requirements of karypopherinα7 (KPNA7), an oocyte and cleavage stage embryo-specific karyopherinαsubtype. We hypothesised that knockdown of KPNA7 would negatively affect porcine cleavage development. To test this hypothesis, in vitro matured and fertilised porcine oocytes were injected with a double-stranded interfering RNA molecule that targeted KPNA7; nuclei were counted in all embryos 6 days after fertilisation. Embryos injected with KPNA7-interfering RNAs possessed significantly lower cell numbers than their respective control groups (P<0.05). In vitro binding assays also suggest that KPNA7 may transport intracellular proteins that possess unique nuclear localisation signals. Our data suggest that embryos have differential requirements for individual karyopherinαsubtypes and that these karyopherinαsubtypes differentially transport intracellular cargo during cleavage development.

Identification of Maturation-Specific Proteins by Single-Cell Proteomics of Human Oocytes

“…For instance, this applies to several maternal effect proteins such as ZAR1 and its paralog ZAR1L (critical for the oocyte-to-embryo transition (41); DPPA3 (required for normal preimplantation development, involved in transcriptional repression, and epigenetic chromatin reprogramming in the zygote (42)); DNMT1 (responsible for maintaining methylation patterns in development (43); TLE6 (important for oocyte developmental competence and embryogenesis (44)); NLRP, OOEP, and PADI6. Other proteins that have only been identified in oocytes are the hormone GPHA2 and the oxytocin carrier protein neurophysin (OXT), as well as KPNA7, an oocyte-specific nuclear importin required for fertility in mice (45,46). The most salient findings of these analyses are summarized in Fig.…”

Autosomal recessive mutations in nuclear transport factor KPNA7 are associated with infantile spasms and cerebellar malformation

“…KPNA7 is highly expressed in bovine and porcine ovarian tissues, oocytes, and embryos. 27,28 In mice, truncating mutations resulted in reduced reproductive potential and female lethality. 25 These expression patterns are interesting as one of our subjects had ambiguous genital findings both at birth and on subsequent examination, without identifiable endocrine disturbance.…”

Functional characterization of importin α8 as a classical nuclear localization signal receptor

“…Importin α8 is the most recently identified importin α family member in a number of species [14][15][16][17][18][19]. Importin α8 is expressed in oocytes and embryos [14,15,18], and importin α8…”