Molecular aspects of chromosome end regions in Sciaridae dipterans

• Grant number: 17/02588-6
• Support Opportunities: Regular Research Grants
• Start date: June 01, 2017
• End date: July 31, 2019
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Eduardo Gorab
• Grantee: Eduardo Gorab
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Dipterans belonging to the Sciaridae family display nuclear features that have not beeen observed in species currently in the Order. With regard to telomeric regions, short repetitive sequences were characterised in Rhynchosciara americana, in contrast to telomere retrotransposons of Drosophila as well as complex repeats in chironomid species. However, processes and mechanims involved in the surprising diversity of chromosome end structures of dipterans have not been proposed to date. Part of this project will exploit two sciarid genera, Trichomegalosphys pubescens and R. americana, in order to propose how chromosome termini have diverged in the two organisms. Nucleolar organisers in Sciaridae appear unusually fragmented and dispersed in the salivary gland in the form of micronucleoli. These nucleolar sub-units may be associated with specific regions of polytene chromosmes while, in cells undergoing division, the rDNA is predominantly localised in a single distal region of a single chromosome. The project will be complemented with further studies on the most dramatic case of nucleolar dispersion that has been observed so far, Schwenkfeldina sp., in order to characterise the rDNA localisation in chromosomes from different tissues, distinct developmental stages and, in addition, to investigate in this species a putative mechanism that restores the rDNA copy number in polytene cells relative to diploid tissues. The proposal is based on papers published by the group that were supported by previous grants from FAPESP (AU)

Scientific publications

(4)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

GORAB, EDUARDO. Triple-Helical DNA in Drosophila Heterochromatin. CELLS, v. 7, n. 12, DEC 2018. (17/02588-6, 13/03840-0)

GORAB, EDUARDO. Chromosome End Diversification in Sciarid Flies. CELLS, v. 9, n. 11, NOV 2020. (17/02588-6)

GORAB, EDUARDO; PEARSON, PETER LEES. Thiazole Orange as an Alternative to Antibody Binding for Detecting Triple-helical DNA in Heterochromatin of Drosophila and Rhynchosciara. JOURNAL OF HISTOCHEMISTRY & CYTOCHEMISTRY, v. 66, n. 3, p. 143-154, MAR 2018. (13/03840-0, 17/02588-6)

AMABIS, JOSE MARIANO; GORAB, EDUARDO. Dramatic nucleolar dispersion in the salivary gland of Schwenkfeldina sp. (Diptera: Sciaridae). SCIENTIFIC REPORTS, v. 11, n. 1, APR 16 2021. (17/02588-6)