ABSTRACT
The synaptonemal complex (SC) is a meiosis-specific proteinaceous macromolecular structure that assembles between paired homologous chromosomes during meiosis in various eukaryotes. The SC has a highly conserved ultrastructure and plays critical roles in controlling multiple steps in meiotic recombination and crossover formation, ensuring accurate meiotic chromosome segregation. Recent studies in different organisms, facilitated by advances in super-resolution microscopy, have provided insights into the macromolecular structure of the SC, including the internal organization of the meiotic chromosome axis and SC central region, the regulatory pathways that control SC assembly and dynamics, and the biological functions exerted by the SC and its substructures. This review summarizes recent discoveries about how the SC is organized and regulated that help to explain the biological functions associated with this meiosis-specific structure.
Subject(s)
Animals , Chromosome Segregation , Meiosis/physiology , Synaptonemal Complex/physiologyABSTRACT
Proper chromosome separation in both mitosis and meiosis depends on the correct connection between kinetochores of chromosomes and spindle microtubules.Kinetochore dysfunction can lead to unequal distribution of chromosomes during cell division and result in aneuploidy,thus kinetochores are critical for faithful segregation of chromosomes.Centromere protein A (CENP-A) is an important component of the inner kinetochore·plate.Multiple studies in mitosis have found that deficiencies in CENP-A could result in structural and functional changes of kinetochores,leading to abnormal chromosome segregation,aneuploidy and apoptosis in cells.Here we report the expression and function of CENP-A during mouse oocyte meiosis.Our study found that microinjection of CENP-A blocking antibody resulted in errors of homologous chromosome segregation and caused aneuploidy in eggs.Thus,our findings provide evidence that CENP-A is critical for the faithful chromosome segregation during mammalian oocyte meiosis.
ABSTRACT
The presence of derivative chromosome in a child with phenotypic features necessitates the need of parental karyotyping to ascertain the exact amount of loss or gain of the genetic material. The aim of this study was to emphasize the importance of parental karyotyping. Cytogenetic evaluation of the proband and his father were carried out at Laboratory. Cytogenetic analysis was performed on phytohemagglutinin stimulated cultures. The derivative chromosome 11 in proband was ascertained to have additional material from chromosome 6p arising from complex chromosomal rearrangement in the father. Karyotyping is the basic, cost-effective preliminary investigation in a child with mental subnormality or congenital anomalies.
Subject(s)
Adult , Child, Preschool , Chromosomes, Human, Pair 3/genetics , Chromosomes, Human, Pair 6/genetics , Chromosomes, Human, Pair 11/genetics , Genetic Counseling , Humans , Intellectual Disability/diagnosis , Intellectual Disability/epidemiology , Intellectual Disability/genetics , /methods , Male , Translocation, GeneticABSTRACT
Objective:To construct the eukaryotic expression plasmid of EGFP/H2B and express it in the Human embryo kidney cells(HEK293).Methods:Part H2B gene was obtained by RT-PCR from cultured HEK293 cell's whole RNA.The sequence encoding H2B was cloned into pEGFP-C1 to construct the eukaryotic expression vector.After confirmed by enzymatic digestion and sequencing,the recombination plasmid was transfected to HEK293 cells by lipofectamine technology for observation of the fusion protein's expression.Results:The recombination plasmid of pEGFP/H2B was constructed successfully.Compared with the dispersing green fluorescence among the whole cells in the control cells transfected with the mock plasmid(pEGFP-C1),the green fluorescence was concentrated in the nuclei of HEK293 cells transfected with pEGFP/H2B and distributed with the chromosomes in the mitotic cells.Conclusions:The successful construction of pEGFP/H2B recombination plasmids establishes an available survey system to study the chromosome segregation mechanism.
ABSTRACT
OBJECTIVE To study the expression of CSE1L gene sifted from the whole genome expression profiling in the aRNA from homogenous human nasopharyngeal carcinoma (NPC) and non-NPC biopsy tissue samples using semi-quantitative RT-PCR (sqRT-PCR). METHODS CSE1L gene was sifted from the whole genome expression profiling from homogenous NPC and non-NPC biopsy tissue samples. RNA later RNA Stabilization Reagent was used to preserve the tissue samples harvested from the nasopharynx of NPC and non-NPC patients. The samples were microdissected to get the homogenous tissue cells and then the total RNA was isolated from them. The antisense RNA (aRNA) was amplified from the total RNA by “in vitro transcription” (IVT). CSE1L gene expression in the homogenous tumor cells of NPC and the pure epithelial pillar cells of normal nasopharyngeal tissue was investigated by sqRT-PCR. RESULTS The high quality total RNA could be harvested from the microdissected homogenous tissue cells, and then the sufficient aRNA was amplified from it. The expression of CSE1L gene was identified using these aRNA by sqRT-PCR. There were significantdifference between the average expression value of CSE1L in NPC tissue (1.740?1.105) and in non-NPC tissue (0.618?0.183; df=30, t=3.159, P=0.004). The expression of CSE1L gene in the whole expression profiling were 1.056?0.296 in NPC tissue and 0.465?0.835 in non-NPC tissue respectively (df=16, t=4.317, P=0.001) . CONCLUSION The whole genome expression profiling with sqRT-PCR could be used to sift the marker genes from biopsy tissue samples. CSE1L may be as a candidate oncogene in NPC.