General characteristics of the polytene chromosomes from ovarian pseudonurse cells of theDrosophila melanogaster otu 11 andfs(2)B mutants

Mal'ceva, N. I.; Gyurkovics, Henrik; Жимулев, И. Ф.

doi:10.1007/bf00710713

Cited by 23 publications

(17 citation statements)

References 21 publications

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“…The concept has two groups of facts to rely on: (i) Cytogenetic observations of coordinated changes in IH and PH at a varying temperature and amount of heterochromatin in the nucleus (14) and, additionally, data on a parallel reduction in DNA underreplication in IH and PH of polytene chromosomes of pseudonurse cells of the otu mutants and decreasing of position effect variegation (25,26).…”

Section: Discussionmentioning

confidence: 99%

Su(UR)ES: A gene suppressing DNA underreplication in intercalary and pericentric heterochromatin ofDrosophila melanogasterpolytene chromosomes

Belyaeva

Жимулев²,

Volkova³

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

132

197

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A genetic locus suppressing DNA underreplication in intercalary heterochromatin (IH) and pericentric heterochromatin (PH) of the polytene chromosomes of Drosophila melanogaster salivary glands, has been described. Found in the In(1)sc V2 strain, the mutation, designated as Su(UR)ES, was located on chromosome 3L at position 34.8 and cytologically mapped to region 68A3-B4. A cytological phenotype was observed in the salivary gland chromosomes of larvae homozygous and hemizygous for Su(UR)ES: (i) in the IH regions, that normally are incompletely polytenized and so they often break to form ''weak points,'' underreplication is suppressed, breaks and ectopic contacts disappear; (ii) the degree of polytenization in PH grows higher. That is why the regions in chromosome arm basements, normally ␤-heterochromatic, acquire a distinct banding pattern, i.e., become euchromatic by morphological criteria; (iii) an additional bulk of polytenized material arises between the arms of chromosome 3 to form a fragment with a typical banding pattern. Chromosome 2 PH reveals additional ␣-heterochromatin. Su(UR)ES does not affect the viability, fertility, or morphological characters of the imago, and has semidominant expression in the heterozygote and distinct maternal effect. The results obtained provide evidence that the processes leading to DNA underreplication in IH and PH are affected by the same genetic mechanism.

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Section: Discussionmentioning

confidence: 99%

Su(UR)ES: A gene suppressing DNA underreplication in intercalary and pericentric heterochromatin ofDrosophila melanogasterpolytene chromosomes

Belyaeva

Жимулев²,

Volkova³

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

132

197

View full text Add to dashboard Cite

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“…4). The region has a clear cut structure, probably due to a general decrease of the formation of ectopic contacts in ovarian chromosomes [Mal'ceva et al, 1995]. At the light microscopical level, we saw eight bands.…”

Section: Position-effect Variegation In Sg and Nc Polytene Chromosomesmentioning

confidence: 95%

“…Chromosome maps of Mal'ceva et al [1995] were used to identify regions in the ovarian polytene chromosomes. The salivary gland polytene chromosomes used in comparison were from the larvae at Puff Stages (PSs) 3-6.…”

Section: Cytological Proceduresmentioning

confidence: 99%

Nurse cell polytene chromosomes ofDrosophila melanogaster otu mutants: Morphological changes accompanying interallelic complementation and position effect variegation

et al. 1997

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Combinations of certain mutant alleles of the ovarian tumor gene permit the production of viable eggs. Two alleles that behave in this way are otu7 and otu1. Females homozygous for either allele are sterile, and their ovarian nurse cells (NC) contain giant polytene chromosomes of various morphologies. Fertile flies (otu+ / otu+, otu− / otu7, otu+ / otu11) have endopolyploid nurse cells with typical dispersed chromosomes. Fertile hybrids (otu7 / otu11) produce large numbers of polytene chromosomes comparable to, and often larger than, classic salivary gland (SG) chromosomes. Therefore, these otu hybrids provide a unique system for studying, at the chromosomal level, the activation and expression of genes functioning during oogenesis. The otu gene encodes a long and a short isoform. The normal long isoform appears to be responsible for the dispersion of chromosomes during the endomitotic DNA replications occurring in ovarian NCs. The genetic inactivation of euchromatic genes placed next to pericentric heterochromatin by a chromosomal rearrangement is accompanied by the compaction of corresponding chromosome regions. A comparative study of the manifestation of position‐effect variegation for the polytene chromosomes of SG cells and NCs was made using the Dp(1;1)pn2b and Dp(1;f)1337 rearrangements. The percentage frequencies of block formation in the SG and NC nuclei for Dp (1;1) pn2b rearrangement were 92.6% vs. 15.8%, respectively; for Dp(1;f) 1337, these values were 56.8% vs. 9.7%. Therefore heterochromatin belonging to germ line chromosomes is in a configuration that is far less likely to inactivate inserted segments of euchromatin than is heterachromatin from somatic chromosomes. Dev. Genet. 20:163–174. 1997. © 1997 Wiley‐Liss, Inc.

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“…Nurse cell chromosomes that fail to disperse are also observed in certain alleles of ovarian tumor (otu) (King et al, 1981;King and Storto, 1988;Heino, 1989;Mal'ceva and Zhimulev, 1993;Heino, 1994;Mal'ceva et al, 1995). otu produces two protein isoforms, Otu98 and Otu104, by alternative splicing of a 126 bp exon.…”

Section: The Ovarian Tumor Gene Can Rescue the Nurse Cell Nuclear Mormentioning

confidence: 99%

Hrb27C, Sqd and Otu cooperatively regulategurkenRNA localization and mediate nurse cell chromosome dispersion inDrosophilaoogenesis

2004

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Heterogeneous nuclear ribonucleoproteins, hnRNPs, are RNA-binding proteins that play crucial roles in controlling gene expression. In Drosophilaoogenesis, the hnRNP Squid (Sqd) functions in the localization and translational regulation of gurken (grk) mRNA. We show that Sqd interacts with Hrb27C, an hnRNP previously implicated in splicing. Like sqd, hrb27C mutants lay eggs with dorsoventral defects and Hrb27C can directly bind to grk RNA. Our data demonstrate a novel role for Hrb27C in promoting grk localization. We also observe a direct physical interaction between Hrb27C and Ovarian tumor (Otu), a cytoplasmic protein implicated in RNA localization. We find that some otu alleles produce dorsalized eggs and it appears that Otu cooperates with Hrb27C and Sqd in the oocyte to mediate proper grklocalization. All three mutants share another phenotype, persistent polytene nurse cell chromosomes. Our analyses support dual cooperative roles for Sqd,Hrb27C and Otu during Drosophila oogenesis.

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General characteristics of the polytene chromosomes from ovarian pseudonurse cells of theDrosophila melanogaster otu 11 andfs(2)B mutants

Cited by 23 publications

References 21 publications

Su(UR)ES: A gene suppressing DNA underreplication in intercalary and pericentric heterochromatin ofDrosophila melanogasterpolytene chromosomes

Su(UR)ES: A gene suppressing DNA underreplication in intercalary and pericentric heterochromatin ofDrosophila melanogasterpolytene chromosomes

Nurse cell polytene chromosomes ofDrosophila melanogaster otu mutants: Morphological changes accompanying interallelic complementation and position effect variegation

Hrb27C, Sqd and Otu cooperatively regulategurkenRNA localization and mediate nurse cell chromosome dispersion inDrosophilaoogenesis

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