KIFC1 is essential for acrosome formation and nuclear shaping during spermiogenesis in the lobster Procambarus clarkii

Expression pattern and functional analysis of kinesin-14 KIFC1 in spermatogenesis of Macaca mulatta

C-terminal kinesin motor KIFC1 is increasingly concerned with an essential role in germ cell development. During the spermatogenesis of mice, rats, and crustaceans, KIFC1 functions in regulating meiotic chromosome separation, acrosome vesicle transportation, and nuclear morphology maintenance. The expression pattern of KIFC1 is conservatively concentrated at the acrosome and nucleus of haploid sperm cells. However, whether KIFC1 has similar functions in non-human primates remains unknown. In this study, we constructed the testis-specific cDNA library and cloned different transcripts of KIFC1 based on the genomic sequence. New variants of KIFC1 were identified, and showed different functional domains from the predicted isoforms. The spatio-temporal expression of KIFC1 proteins in seminiferous tubules of rhesus monkeys showed an obvious nuclear localization, specifically expressed in the spermatocytes and early haploid spermatids. The transcripts of KIFC1 also exhibited considerable expression in the nucleus of rhesus LLC-MK2 cells. Besides, we demonstrated that KIFC1 located at the acrosome and microtubule flagella of the mature sperm, and KIFC1 inhibition resulted in sperm tail deformation as well as increased the instability of head-to-tail connection. In summary, this study filled a gap in the reproductive research of the KIFC1 gene in non-human primates.

Transcriptome analysis of the testes of male chickens with high and low sperm motility

The reproductive performance of chicken breeders has significant economic importance in the poultry industry, and sperm motility is an indicator of reproductive performance. This study performed RNA-seq of the testes of Gushi chicken roosters with high and low sperm motility and identified differentially expressed RNAs involved in sperm motility. RNA-seq analysis showed that 73 and 67 differentially expressed mRNAs were up- and downregulated, and 47 and 56 differentially expressed long non-coding RNAs were up- and downregulated, respectively. The genes related to sperm motility and spermatogenesis included KIFC1, KCNK2, and REC8. Functional enrichment analysis revealed that the pathways related to sperm motility included oxidative phosphorylation and glycine, serine, and threonine metabolism. In addition, the MSTRG.15920.1-REC8-MSTRG.11860.2-VWC2 pathway may regulate sperm motility. This study helped elucidate the molecular genetic mechanism of sperm motility in chicken.

Prognostic Value and Immunological Role of KIFC1 in Hepatocellular Carcinoma

As one of the members of the kinesin family, the role and potential mechanism of kinesin family member C1 (KIFC1) in the development of liver hepatocellular carcinoma (LIHC), especially in the immune infiltration, have not been fully elucidated. In this study, multiple databases and immunohistochemistry were employed to analyze the role and molecular mechanism including the immune infiltration of KIFC1 in LIHC. Generally, KIFC1 mRNA expression was overexpressed in LIHC tissues than normal tissues, and its protein was also highly expressed in the LIHC. KIFC1 mRNA expression was correlated with tumor grade and TNM staging, which was negatively correlated with overall survival and disease-free survival. Moreover, univariable and multivariate Cox analysis revealed that upregulated KIFC1 mRNA is an independent prognostic factor for LIHC. The KIFC1 promoter methylation level was negatively associated with KIFC1 mRNA expression and advanced stages and grade in LIHC. The different methylation sites of KIFC1 had a different effect on the prognosis of LIHC. Specifically, the KIFC1 mRNA expression level showed intense correlation with tumor immunity, such as tumor-infiltrating immune cells and immune scores as well as multiple immune-related genes. Moreover, KIFC1 co-expressed with some immune checkpoints and related to the responses to immune checkpoint blockade (ICB) and chemotherapies. Significant GO analysis showed that genes correlated with KIFC1 served as catalytic activity, acting on DNA, tubulin binding, histone binding, ATPase activity, and protein serine/threonine kinase activity. KEGG pathway analysis showed that these genes related to KIFC1 are mainly enriched in signal pathways such as cell cycle, spliceosome, pyrimidine metabolism, and RNA transport. Conclusively, KIFC1 was upregulated and displayed a prognostic value in LIHC. Moreover, KIFC1 may be involved in the LIHC progression partially through immune evasion and serve as a predictor of ICB therapies and chemotherapies.

Homologues of Piwi control transposable elements and development of male germline in Penaeus monodon

PIWI belongs to the Argonaute protein family, which is a major protein component in RNA silencing pathway. Piwi proteins play roles in the control of transposons and germline development. They have been widely studied in vertebrates and flies, while very little is known in crustacean so far. We have previously identified and characterized a cDNA encoding Piwi protein (PmPiwi1) in the black tiger shrimp Penaeus monodon. In this study, a cDNA encoding another Piwi protein namely PmPiwi2 was identified by rapid amplification of cDNA ends (RACEs). PmPiwi2 was expressed solely in shrimp testis and ovary, indicating its potential role in germ cell development. Similar to PmPiwi1, PmPiwi2 also plays a part in the control of transposons as PmPiwi2-knockdown shrimp showed a significant increase in the expression of gypsy2 retrotransposon and mariner element in the testis. In addition, a reduction of sperm numbers in the spermatophore of PmPiwi2-knockdown shrimp suggests that PmPiwi2 is required for spermatogenesis similar to PmPiwi1. This study further demonstrated that apoptotic cell death was strongly detected in spermatogonia and spermatocyte cells of both PmPiwi-knockdown shrimp and thus, could be the cause of reduced sperm count. Investigation of sperm morphology showed a remarkably high proportion of abnormal sperms in the spermatophore of the PmPiwi1-knockdown shrimp, while PmPiwi2-knockdown shrimp had comparable percentage of abnormal sperms to the control shrimp. Consistently, the expression of KIFC1, a gene that is necessary for spermiogenesis was significantly reduced upon PmPiwi1 silencing, but not in the PmPiwi2-knockdown shrimp. Our results suggested that while both PmPiwis are required for the development of spermatid, only PmPiwi1 is possibly involved in the final stage of sperm maturation.

KIFC1 is essential for normal spermatogenesis and its depletion results in early germ cell apoptosis in the Kuruma shrimp, Penaeus (Marsupenaeus) japonicus

In order to explore the dynamic mechanisms during spermatogenesis of the penaeid prawns, the full length of kifc1 was cloned from testis cDNA of Penaeus japonicus through RACE. Both semi-quantitative RT-PCR and Western blot results indicated that KIFC1 was extensive expressed in different tissue of P. japonicus. Compared with other tissue, the highest expression of KIFC1 occurred in the testis. According to the immunofluorescence results, the KIFC1 protein was detected at each stage of whole process of spermatogenesis. In the spermatogonial phase, KIFC1 mainly dispersed in cytoplasm and co-localized with microtubules, while abundant KIFC1 signal was detected in the nucleus of spermatocytes. At the early stage of spermatids, KIFC1 was transported from the nucleus into the cytoplasm, and it assisted microtubule assembly onto one side of the nucleus. Finally, in mature sperm, it was weakly expressed in the acrosome. This implies that KIFC1 may participate in the mitosis of spermatogonia, meiosis of spermatocyte, and acrosome formation during spermiogenesis; it may also play functions in acrosome maintaining in mature sperm. In addition, the results of KIFC1 knockdown by dsRNA injection in vivo reveal that decreased KIFC1 expression may induce aberrant microtubule assembly, and it leads to spermatogonia and spermatocyte apoptosis.

salto/CG13164 is required for sperm head morphogenesis in Drosophila

Producing mature spermatozoa is essential for sexual reproduction in metazoans. Spermiogenesis involves dramatic cell morphological changes going from sperm tail elongation and nuclear reshaping to cell membrane remodeling during sperm individualization and release. The sperm manchette plays a critical scaffolding function during nuclear remodeling by linking the nuclear lamina to the cytoskeleton. Here, we describe the role of an uncharacterized protein in Drosophila, salto/CG13164, involved in nuclear shaping and spermatid individualization. Salto has dynamic localization during spermatid differentiation, being progressively relocated from the sperm-nuclear dense body, which is equivalent to the mammalian sperm manchette, to the centriolar adjunct and acrosomal cap during spermiogenesis. salto-null male flies are sterile and exhibit complete spermatid individualization defects. salto-deficient spermatids show coiled spermatid nuclei at late maturation stages and stalled individualization complexes. Our work sheds light on a novel component involved in cytoskeleton-based cell-morphological changes during spermiogenesis.

Transcriptome Dynamics During Turbot Spermatogenesis Predicting the Potential Key Genes Regulating Male Germ Cell Proliferation and Maturation

Spermatogenesis is a dynamic developmental process in which spermatogonial stem cells proliferate, differentiate and mature into functional spermatozoa. These processes require an accurate gene regulation network. Here, we investigated the dynamic changes that occur during spermatogenesis through a combination of histological and transcriptome analyses of different developmental stages of the testis. We constructed 18 testis transcriptome libraries, and the average length, N50, and GC content of the unigenes were 1,795 bp; 3,240 bp and 49.25%, respectively. Differentially expressed genes (DEGs) that were related to germ cell proliferation and maturation, such as NANOS3, RARs, KIFs, steroid hormone synthesis-related genes and receptor genes, were identified between pairs of testis at different developmental stages. Gene ontology annotation and pathway analyses were conducted on DEGs with specific expression patterns involved in the regulation of spermatogenesis. Nine important pathways such as steroid hormone biosynthesis related to spermatogenesis were identified. A total of 21 modules that ranged from 49 to 7,448 genes were designed by a weighted gene co-expression network analysis. Furthermore, a total of 83 candidate miRNA were identified by computational methods. Our study provides the first transcriptomic evidence for differences in gene expression between different developmental stages of spermatogenesis in turbot (Scophthalmus maximus).

Export of membrane proteins from the Golgi complex to the primary cilium requires the kinesin motor, KIFC1

Microtubule-based motors contribute to the efficiency and selectivity of Golgi exit and post-Golgi transport of membrane proteins that are targeted to distinct compartments. Cytoplasmic dynein moves post-Golgi vesicles that carry rhodopsin toward the base of the connecting cilium in photoreceptor cells; however, the identity of the motors that are involved in the vesicular trafficking of ciliary membrane proteins in nonphotoreceptor cells remains unclear. Here, we demonstrate that the minus end-directed kinesin KIFC1 (kinesin family member C1) is required for both ciliary membrane protein transport and serum starvation-induced ciliogenesis in retinal pigmented epithelial 1 cells. Although KIFC1 is known as a mitotic motor that is sequestered in the nucleus during interphase, KIFC1 immunoreactivity appeared in the Golgi region after serum starvation. Knockdown of KIFC1 inhibited the export of ciliary receptors from the Golgi complex. KIFC1 overexpression affected the Golgi localization of GMAP210 (Golgi microtubule-associated protein 210) and IFT20 (intraflagellar transport 20), which are involved in membrane protein transport to cilia. Moreover, KIFC1 physically interacted with ASAP1 (ADP-ribosylation factor GTPase-activating protein with SH3 domain, ankyrin repeat and PH domain 1), which regulates the budding of rhodopsin transport carriers from the Golgi complex, and KIFC1 depletion caused Golgi accumulation of ASAP1. A decrease in the centrosomal levels of IFT20 and TTBK2 (τ-tubulin kinase 2) was associated with ciliogenesis defects in KIFC1-depleted cells. Our results suggest that KIFC1 plays roles in the Golgi exit of ciliary receptors and in the recruitment of ciliogenesis regulators.-Lee, S.-H., Joo, K., Jung, E. J., Hong, H., Seo, J., Kim, J. Export of membrane proteins from the Golgi complex to the primary cilium requires the kinesin motor, KIFC1.