Mitotic Kinesin-Like Protein 1 (MKLP1/KIF23) in hereditary congenital dyserythropoietic anemia type III and in cancer

A hereditary form of autosomal dominant congenital dyserythropoietic anaemiatype III (CDA III) has been reported in four families from Sweden, Argentina, Cuba and USA. CDA III patients might experience signs of mild anaemia and some of them need occasional blood transfusions. Other clinical features seen in CDA III patients are retinal angioid streaks, monoclonal gammopathy of undetermined significance and multiple myeloma. Their bone marrow is characterised by presence of giant erythroblasts with up to 12 nuclei. Previously, CDA III was mapped to a region on chromosome 15q21-q25. In this study we aimed to identify the genetic cause of CDA III, investigate the reasons why erythroid lineage in the patients’ bone marrow is mostly affected, and seek the explanation of increased rate of cancer in the Swedish CDA III family. We identified the genetic cause of CDA III using targeted next generation sequencing. A novel missense mutation c.2747C&gt;G, p.P916R in kinesin familymember 23 gene (KIF23) segregated with the disease in both the American and Swedish family, and was absent in databases of sequence variants from healthy individuals. Knock-down and rescue experiments in HeLa Kyoto cells showed that the P916R mutation caused cytokinesis failure which resulted in large cells with several nuclei. This was consistent with the CDA III phenotype. To reveal interaction partners of wild-type and mutant KIF23 proteins, pull-down experiments followed by mass spectrometry and Western blot analysis were performed. This identified Coatomer Protein Complex I (COPI), a vesicle forming complex responsible for intracellular transport, as a KIF23 interactor. By using immunofluorescence and fluorescence microscopy, we showed that COPI subunits COPα and COPβ localize to the midbody during cytokinesis. These findings indicate involvement of vesicle transport proteins in mitosis and cytokinesis, though the significance of COPI-KIF23 interaction in cell division remains to be uncovered. To address the question if other cells are affected by the KIF23 P916R mutation, we created a knock-in mouse model with Kif23 c.2726C&gt;G, p.P909R, which corresponds to the human KIF23 c.2747C&gt;G. However, the mice did not developany phenotype indicating CDA III. This result was consistent with the studies ofother CDA subtypes where mouse models failed, suggesting that CDA occur only in humans. Our study of human and mouse KIF23/Kif23 expression revealed novel, previously not annotated transcripts, one in human and two in mice. Expression analysis of total mRNA using droplet digital PCR demonstrated an extensive variation of KIF23 and Kif23 expression levels in all tissues. The shortest Kif23 transcript lacking exon 17 and 18 was prevalent in mice, while corresponding transcript in human was the least expressed. Considering the importance of KIF23 in cytokinesis and KIF23 association with cancer, we hypothesized that somatic KIF23 mutations might be overrepresented in cancer. For this purpose, we screened KIF23 and its promoter in non-small cell lung cancer samples that previously demonstrated KIF23 overexpression. No pathogenic driving KIF23 variants were detected by Sangersequencing; however, subsequent genome-wide genotyping (SNP-array) detected gain of chromosome 15 in most cases that could possibly explain KIF23 overexpression.P.g.a. covid 19 uppmanas åhörare att delta digitalt via Zoom. Länk: https://umu.zoom.us/j/65108113265</p

Differential tissue specific expression of Kif23 alternative transcripts in mice with the human mutation causing congenital dyserythropoietic anemia type III

Kinesin Family Member 23 (KIF23), a cell cycle regulator, has a key task in cytokinesis. KIF23 over-expression in cancer has been associated with tumor growth, progression, and poor prognosis, indicating a potential to be a cancer biomarker. A mutation in KIF23 (c.2747C &gt; G, p.P916R) was shown to cause congenital dyserythropoietic anemia, type III (CDA III). To-date, fifteen KIF23 transcripts have been annotated, but their expression is poorly investigated. We hypothesized that tissue specific expression of a particular transcript can be critical for CDA III phenotype. In this study, we quantified expression of alternative Kif23 transcripts in a mouse model with human KIF23 mutation and investigated its association with a regulator of alternative splicing, serine/arginine-rich splicing factor 3 (Srsf3). We confirmed presence of an additional exon 8 in both human and mouse KIF23 transcripts. A transcript lacking exons 17 and 18 was ubiquitously expressed in mice while other isoforms were common in human tissues however in bone marrow of knock-in mice a transcript without exon 18 was prevalent as it was in bone marrow of a CDA III patient. We conclude that the possibility that the tissue specific expression of KIF23 alternative transcripts influence the CDA III phenotype cannot be neglected

Uvajanje koncepta učeče se organizacije v trgovinsko podjetje

Background: Congenital dyserythropoietic anemia type III (CDA III) can be caused by mutation in KIF23. CDA III differs from CDA I and II in the sense that secondary hemochromatosis has not been reported. However, we have observed elevated serum ferritin in a CDA III family. Since primary hemochromatosis is common in Northern Europe we decided to screen the family for HFE mutations. Aim: Study clinical appearance and prevalence of HFE gene mutations, C282Y and H63D, in a CDA III family.  Methods: DNA from 37 CDA III patients and 21 non-affected siblings was genotyped. Iron status from EDTA plasma was measured in 32 of the CDA III patients and 18 of the non-affected siblings. Results: Out of 37 CDA III patients, 18 carried heterozygous HFE mutations and six were compound heterozygotes. Out of 21 CDA III negative siblings, nine had heterozygous HFE mutations, two were homozygous (one H63D and one C282Y), and two were compound heterozygous. None of the patients with wt HFE, regardless of CDA III status, suffered from iron overload. Four patients with HFE mutations needed treatment with phlebotomy to normalize ferritin and transferrin iron saturation; one CDA III negative patient with homozygous C282Y, two CDA III patients with heterozygous HFE mutations and one CDA III case with compound heterozygosity. Conclusion: HFE mutations were found in 65 % of CDA III patients and in 62 % of their CDA III negative siblings. Heterozygous HFE mutation, C282Y and even H63D, can cause iron overload when occurring concomitantly with CDA III

Mutation analysis and copy number alterations of KIF23 in non-small-cell lung cancer exhibiting KIF23 over-expression

KIF23 was recently suggested to be a potential molecular target for the treatment of lung cancer. This proposal is based on elevated expression of KIF23 in several tumors affecting breast, lung, brain, and liver, and also on the presence of KIF23 mutations in melanoma and colorectal cancer. Recently, we identified a mutation in the KIF23 gene causing a rare hereditary form of dyserythropoietic anemia (CDA III) with predisposition to blood cancer. We suggested that KIF23 overexpression in tumors might be due to the presence of activating somatic mutations, and therefore, mutation screening of the KIF23 in 15 non-small-cell lung cancer (NSCLC) cases with elevated expression level of KIF23 was undertaken. Eight sequence variants were found in all samples. Furthermore, one variant was present in two cases, and one variant was case specific. Nine variants were previously reported while one variant lacks frequency information. Nine of ten cases available for single nucleotide polymorphism-array analysis demonstrated aberrant karyotypes with additional copy of entire chromosome 15. Thus, no activating somatic mutations in coding regions of the KIF23 were found. Furthermore, no mutations were detected in cell cycle genes homology region in KIF23 promoter responsible for p53-dependent repression of KIF23 expression. We showed that the elevated level of KIF23 could be due to additional copy of chromosome 15 demonstrated in 90% of NSCLC cases analyzed in this study. Considering the crucial role of KIF23 in the final step of mitosis, the gene is a potential molecular marker, and for better understanding of its role in cancer development, more tumors should be analyzed