Meiotic pairing behavior of two free duplications of linkage group I in Caenorhabditis elegans

Rose, Ann M.; Baillie, David L.; Curran, James T.

doi:10.1007/bf00332723

Cited by 70 publications

(54 citation statements)

References 13 publications

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“…We also used the mutations let-389(h428) I (Howell et al 1987), let-400(h269) I, let-520(h690) I (McKim et al 1992), and xol-l(y9) X (Miller et al 1988). We used the deficiency hDf8 (Start et al 1989) and the free duplications sDp2 (Rose et al 1984), hDp58, and hDp62 (McKim and Rose 1990). The sem-4 alleles used are described below.…”

Section: Genetic Methodsmentioning

confidence: 99%

The Caenorhabditis elegans gene sem-4 controls neuronal and mesodermal cell development and encodes a zinc finger protein.

Basson¹,

Horvitz²

1996

Genes Dev.

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The large number of different types of neurons in both vertebrate and invertebrate nervous systems raises the question of how the development of a particular neuronal cell type is specified. To pursue this question, Desai et al. (1988;Desai and Horvitz 1989) initiated a genetic analysis of the HSN serotonergic motor neurons in Caenorhabditis elegans. This analysis identified genes that are required for a number of distinct aspects of HSN development and placed these genes in a pathway of gene action. Some of these genes encode types of proteins that have been shown to control neuronal development in other organisms. Examples of such genes are egl-5, which encodes a homeo domain protein (Wang et al. 1993); unc-6, which encodes a member of the netrin family {Serafini et al. 1994); unc-33, which encodes a protein that is related to CRMP-62, a chick collapsin response mediator protein (Goshima et al. 1995); and unc-86, which encodes a POU homeo domain protein (Finney and Ruvkun 1990). This correlation between the types of proteins that control HSN development and the types of proteins that control neuronal development in other organisms suggests that study of HSN development will reveal general principles of how neuronal cell type is specified.~Corresponding author.The POU gene unc-86 is required for the normal pattern of HSN axonal outgrowth, normal HSN nuclear morphology, and HSN serotonin expression (Desai et al. 1988). POU homeo domain proteins have been shown to be required for neuronal development in both Drosophila (Bhat et al. 1995;Yeo et al. 1995) and mammals (for review, see Sharp and Morgan 1996). Mutation of the C. elegans gene sere-4 (sex muscle defective) causes the same spectrum of defects in HSN development as that caused by mutation of unc-86 (Desai et al. 1988). Because POU homeo domain proteins seem likely to play an evolutionarily conserved role in neuronal development, we are interested in determining how the SEM-4 and UNC-86 proteins interact in controlling HSN development. To understand how sem-4 functions in HSN development as well as in the development of other cell types, we have performed a genetic and molecular analysis of sere-4.

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Section: Genetic Methodsmentioning

confidence: 99%

The Caenorhabditis elegans gene sem-4 controls neuronal and mesodermal cell development and encodes a zinc finger protein.

Basson¹,

Horvitz²

1996

Genes Dev.

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“…(37) Similar observations were made with duplications of the X chromosome (39) and the autosomes. (40,41) For example, crossing over between the free duplication sDp2(1:f) and the regular chromosome I was rare, occurring at a frequency of <10 4 even though the expected frequency based on the genetic length of the same interval on the intact chromosome I was 25%. (40) Conversely, a duplication carrying the PC end of chromosome I engaged in crossing over frequently.…”

Section: Meiosis: Juggling Synapsis and Recombinationmentioning

confidence: 97%

When specialized sites are important for synapsis and the distribution of crossovers

Joyce

McKim

2007

BioEssays

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In C. elegans and D. melanogaster, specialized sites have an important role in meiotic recombination. Recent evidence has shown that these sites in C. elegans have a role in synapsis. Here we compare the initiation of synapsis in organisms with specialized sites and those without. We propose that, early in prophase, synapsis requires an initiator to overcome inhibitory factors that function to prevent synaptonemal complex (SC) formation between nonhomologous sequences. These initiators of SC formation can be stimulated by crossover sites, possibly other types of recombination sites and also specialized sites where recombination does not occur.

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“…In 20 oocyte nuclei of each genotype, we observed HIM-3 staining at the cores of both duplications, suggesting that the duplications were organized about a single core, like the other chromosomes. The association of HIM-3 with univalents and with sDp2, which is incapable of pairing for recombination with chromosome I because it lacks the HRR (homolog recognition region; Rose et al 1984), indicates that HIM-3 localizes to both recombination competent and incompetent chromosomes. Its recruitment to chromosomes cores is not ubiquitous, however, because it is absent at the core of the lone X chromosome in male spermatocytes.…”

Section: Him-3 Fails To Localize To the Obligately Achiasmate X Chrommentioning

confidence: 99%

Synapsis and chiasma formation in Caenorhabditis elegans require HIM-3, a meiotic chromosome core component that functions in chromosome segregation

Zetka¹,

Kawasaki²,

Strome³

et al. 1999

Genes & Development

268

308

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Meiotic chromosomes are organized about a proteinaceous core that forms between replicated sister chromatids. We have isolated a Caenorhabditis elegans gene, him-3, which encodes a meiosis-specific component of chromosome cores with some similarity to the yeast lateral element protein Hop1p. Antibodies raised against HIM-3 localize the protein to condensing chromosomes in early prophase I and to the cores of both synapsed and desynapsed chromosomes. In RNA interference experiments, chromosomes appear to condense normally in the absence of detectable protein but fail to synapse and form chiasmata, indicating that HIM-3 is essential for these processes. Hypomorphs of him-3, although being synapsis proficient, show severe reductions in the frequency of crossing-over, demonstrating that HIM-3 has a role in establishing normal levels of interhomolog exchange. Him-3 mutants also show defects in meiotic chromosome segregation and the persistence of the protein at the chromosome core until the metaphase I-anaphase I transition suggests that HIM-3 may play a role in sister chromatid cohesion. The analysis of him-3 provides the first functional description of a chromosome core component in a multicellular organism and suggests that a mechanistic link exists between the early meiotic events of synapsis and recombination, and later events such as segregation. [Key Words: C. elegans; chromosome core; synapsis; crossing-over; segregation]Received April 12, 1999; revised version accepted July 19, 1999. Meiosis is two specialized cell divisions that result in daughter cells with half the chromosome number of the parental cell. This is accomplished by a single round of DNA replication followed by two divisions, anaphase I and II. Anaphase I is unique in that it segregates homologous chromosomes, each composed of a pair of sister chromatids joined by a single kinetochore, from each other. Most organisms use crossing-over, cytologically evident as chiasmata, to direct the segregation of chromosomes at this division. A decrease in the frequency of crossing-over generally leads to an increase in the nondisjunction of chromosome pairs (for review, see Hawley 1988). For exchange to occur in most organisms, homologous chromosomes must find one another in the prophase nucleus and align themselves throughout their lengths, a process that usually culminates in the formation of a tripartite proteinaceous structure, the synaptonemal complex (SC) (Moses 1968;von Wettstein et al. 1984;Heyting 1996). A prerequisite to the assembly of the mature SC is the polymerization of single proteinaceous axes between sister chromatids, which have been referred to as axial elements or chromosome cores (Moses 1968). The axial elements of homologous chromosomes become aligned and equidistantly separated by the proteins that constitute the central region of the SC and are then referred to as lateral elements. The conserved, highly ordered nature of the SC has raised questions concerning its function and protein composition. Although the localization of axi...

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Meiotic pairing behavior of two free duplications of linkage group I in Caenorhabditis elegans

Cited by 70 publications

References 13 publications

The Caenorhabditis elegans gene sem-4 controls neuronal and mesodermal cell development and encodes a zinc finger protein.

The Caenorhabditis elegans gene sem-4 controls neuronal and mesodermal cell development and encodes a zinc finger protein.

When specialized sites are important for synapsis and the distribution of crossovers

Synapsis and chiasma formation in Caenorhabditis elegans require HIM-3, a meiotic chromosome core component that functions in chromosome segregation

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