The Gene Encoding the RCC1 (Regulator of Chromosome Condensation 1) Protein in Drosophila melanogaster and Homo sapiens

The <i>RCC1</i> gene is active in ensuring many cellular functions related to cell division in <i>Drosophila melanogaster</i> and <i>Homo sapiens</i>. A detailed comparison of the structure and functions of the <i>RCC1</i> gene in <i>Drosophila melanogaster</i> and <i>Homo sapiens</i> was carried out using different analytical techniques (bioinformatics, immunofluorescence and confocal microscopy, FISH, and molecular genetic methods). The <i>Drosophila RCC1</i> gene belongs to the family of housekeeping genes, since it resides in the interbands and gray bands of polytene chromosomes within aquamarine/lazurite chromatin in <i>D. melanogaster</i>. Furthermore, the databases demonstrate that <i>RCC1</i> in <i>D. melanogaster</i> is expressed in all the tissues at all the developmental stages. According to The Human Protein Atlas, <i>RCC1</i> in humans also exhibits low tissue specificity for 29 tissues. Immunostaining of polytene chromosomes with RCC1 antibodies revealed approximately 260 sites of RCC1 protein localization exclusively in black bands (sites of developmental genes) and in heterochromatin. The size of the coding gene portions is almost identical for <i>D. melanogaster</i> and <i>H. sapiens</i>, being ~2 kb. The group of <i>Drosophila</i> proteins related to condensed chromatin, RCC1 being a member of this group, has homologs forming similar interaction networks in humans. The conserved nature of the <i>RCC1</i> gene has been confirmed by cell cycle studies in both species. It was found that expression of the <i>RCC1</i> gene is upregulated in glioblastoma; the <i>RCC1</i> protein predominantly resides on centrioles during metaphase.