The Function Of Kinesin-12Gene In Meiosis Of Arabidopsis

Kinesin protein is the biggest family among the threecytoskeleton proteins, they are moving along microtubule with thehelp of energy released by ATP hydrolysis, the member of kinesinfamily has approximately350conservative amino acid sequenceand one nucleotide-dependent microtubule binding domain,it isdivided into14subfamily according to sequence homology ofmicrotubule binding domain.Kinesin-12is one member of the14subfamily,and it is microtubule dynein protein.Kinesin-12a andkinesin-12b are different T-DNA insertion mutants, the protein islocated between two antiparallel Phragmoplast microtubule.Atpresent,research on the gene is just in the mitosis.Meiosis,that just occurred in growth and development of sexualreproductive cell, in the process of meiosis,DNA just duplicate onceand cell split twice.meiosis is essential for sexual reproduction,because it can ensure the number of chromosome in forward pass isthe same as that in offspring of organisms,genes are inheritedbetween generations after meiosis,then it can guarantee the inheritance of biological traits,genes may changed as well in theprocess,so,it not only guarantee biological diversity,but alsostrengthen the ability of organisms adapt the myriads of changes inthe environment.The present study use wild type Arabidopsis andkinesin-12a1/12b2(double mutant) as materials,by identifiedmutant、cloned of genes and construction of GFP fusion microtubuleand microfilament vector,and infected wild type Arabidopsis andmutant plants,then we acquired transgenic plants,we also analysedthe phenotype of mutant、identified anther and the vitality of pollenof wild type and mutant、we compared behaviour of chromosomeduring every period in meiosis of microspore mother cell,resultindicated that:1.Results of sequence determination indicated thatrecombinant plasmid vector is correct.2.Result of mutant identity illustrated that mutant ishomozygote.3.For mutant,it appeared early blossoming in vegetativegrowth,and in reproductive growth,plant is short and small,leaf isnarrow, silique is short,the abortion rate of wild type seeds is about21%,but the rate of mutant is63%,the seeds of mutant is abnormal.4.TTC staining of pollen, we counted the abortion rate of wild type pollen is19%,but the rate of mutant is about72%,indicatedthat kinesin-12gene affect the growth of male gametophyte.5.The result of scanning electron microscope indicate that,theanther of wild type Arabidopsis is full,but that of mutant isstir-fried,so we infer that kinesin-12gene may affect the growth ofanther.6.DAPI staining result indicate that,the chromosome ofmicrosporocyte of mutant in meiosis metaphase I and anaphase I isabnormal,it appears lagging chromosome and chromosomebridge,so we infer kinesin-12gene may participate in meiosis,and itfunction in metaphase and anaphase.in the mutant,it can not formspindle in metaphase I and phragmoplast in anaphase I,so it can notregulate the motion of chromosome in metaphase andanaphase,so,we infer the function of the gene is forming spindle andphragmoplast along with microtubule.7.Embryosac observation of wild type Arabidopsis and mutantby confocal laser scanning microscope,we found that Embryo sac ofwild type Arabidopsis has live nucleus,but it only exist in littlemutant,result indicate that kinesin-12gene may affect thedevelopment of female gametophyte.8.indirect immunofluorescence labeling indicate that,there ispolar microtubule in metaphase in microspore of mutant,but it exist in anaphase in theory,so,we infer,one of the function of the gene isto inhibit forming of polar microtubule.