Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.4.4 (kinesin)
 5,033 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mistakes in chromosome segregation lead to aneuploid cells. In somatic cells, aneuploidy is associated with cancer but in gametes, aneuploidy leads to infertility, miscarriages or developmental disorders like Down syndrome. Haploid gametes form through species-specific developmental programs that are coupled to meiosis. The first meiotic division (MI) is unique to meiosis because sister chromatids remain attached while homologous chromosomes are segregated. For reasons not fully understood, this reductional division is prone to errors and is more commonly the source of aneuploidy than errors in meiosis II (MII) or than errors in male meiosis. In mammals, oocytes arrest at prophase of MI with a large, intact germinal vesicle (GV; nucleus) and only resume meiosis when they receive ovulatory cues. Once meiosis resumes, oocytes complete MI and undergo an asymmetric cell division, arresting again at metaphase of MII. Eggs will not complete MII until they are fertilized by sperm. Oocytes also can undergo meiotic maturation using established in vitro culture conditions. Because generation of transgenic and gene-targeted mouse mutants is costly and can take long periods of time, manipulation of female gametes in vitro is a more economical and time-saving strategy. Here, we describe methods to isolate prophase-arrested oocytes from mice and for microinjection. Any material of choice may be introduced into the oocyte, but because meiotically-competent oocytes are transcriptionally silent cRNA, and not DNA, must be injected for ectopic expression studies. To assess ploidy, we describe our conditions for in vitro maturation of oocytes to MII eggs. Historically, chromosome-spreading techniques are used for counting chromosome number. This method is technically challenging and is limited to only identifying hyperploidies. Here, we describe a method to determine hypo-and hyperploidies using intact eggs. This method uses monastrol, a kinesin-5 inhibitor, that collapses the bipolar spindle into a monopolar spindle thus separating chromosomes such that individual kinetochores can readily be detected and counted by using an anti-CREST autoimmune serum. Because this method is performed in intact eggs, chromosomes are not lost due to operator error.
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PMID:Mouse oocyte microinjection, maturation and ploidy assessment. 2180 28

Down syndrome (DS) is a chromosomal disorder caused by chromosome 21 trisomy and is the most frequent genetic cause of intellectual disability. The gene for the kinesin family member 21A (KIF21A), is a member of the kinesin superfamily involved in the anterograde fast axonal transport. In this study, we have evaluated the possible differential expression of KIF21A mRNA, by qRT-PCR, in peripheral blood leukocytes of DS subjects and it compared with the normal population. In the assumption that changes in KIF21A gene expression levels may affect the axonal transport and the development of the nervous system of subjects with DS. In the present case-control study, KIF21A gene expression was increased in 72.72 % of DS samples compared with normal subjects. This finding suggests that changes in the expression levels of KIF21A in DS subjects may affect the axonal transport and the development of the nervous system.
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PMID:KIF21A mRNA expression in patients with Down syndrome. 2296 44