Tags

Type your tag names separated by a space and hit enter

B chromosomes showing active ribosomal RNA genes contribute insignificant amounts of rRNA in the grasshopper Eyprepocnemis plorans.
Mol Genet Genomics. 2014 Dec; 289(6):1209-16.MG

Abstract

The genetic inertness of supernumerary (B) chromosomes has recently been called into question after finding several cases of gene activity on them. The grasshopper Eyprepocnemis plorans harbors B chromosomes containing large amounts of ribosomal DNA (rDNA) units, some of which are eventually active, but the amount of rRNA transcripts contributed by B chromosomes, compared to those of the standard (A) chromosomes, is unknown. Here, we address this question by means of quantitative PCR (qPCR) for two different ITS2 amplicons, one coming from rDNA units located in both A and B chromosomes (ITS2(A+B)) and the other being specific to B chromosomes (ITS2(B)). We analyzed six body parts in nine males showing rDNA expression in their B chromosomes in the testis. Amplification of the ITS2(B) amplicon was successful in RNA extracted from all six body parts analyzed, but showed relative quantification (RQ) values four orders of magnitude lower than those obtained for the ITS(A+B) amplicon. RQ values differed significantly between body parts for the two amplicons, with testis, accessory gland and wing muscle showing threefold higher values than head, gastric cecum and hind leg. We conclude that the level of B-specific rDNA expression is extremely low even in individuals where B chromosome rDNA is not completely silenced. Bearing in mind that B chromosomes carry the largest rDNA cluster in the E. plorans genome, we also infer that the relative contribution of B chromosome rRNA genes to ribosome biogenesis is insignificant, at least in the body parts analyzed.

Authors+Show Affiliations

Departamento de Genética, Facultad de Ciencias, Universidad de Granada, 18071, Granada, Spain.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

24997085

Citation

Ruiz-Estévez, Mercedes, et al. "B Chromosomes Showing Active Ribosomal RNA Genes Contribute Insignificant Amounts of rRNA in the Grasshopper Eyprepocnemis Plorans." Molecular Genetics and Genomics : MGG, vol. 289, no. 6, 2014, pp. 1209-16.
Ruiz-Estévez M, Badisco L, Broeck JV, et al. B chromosomes showing active ribosomal RNA genes contribute insignificant amounts of rRNA in the grasshopper Eyprepocnemis plorans. Mol Genet Genomics. 2014;289(6):1209-16.
Ruiz-Estévez, M., Badisco, L., Broeck, J. V., Perfectti, F., López-León, M. D., Cabrero, J., & Camacho, J. P. (2014). B chromosomes showing active ribosomal RNA genes contribute insignificant amounts of rRNA in the grasshopper Eyprepocnemis plorans. Molecular Genetics and Genomics : MGG, 289(6), 1209-16. https://doi.org/10.1007/s00438-014-0880-y
Ruiz-Estévez M, et al. B Chromosomes Showing Active Ribosomal RNA Genes Contribute Insignificant Amounts of rRNA in the Grasshopper Eyprepocnemis Plorans. Mol Genet Genomics. 2014;289(6):1209-16. PubMed PMID: 24997085.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - B chromosomes showing active ribosomal RNA genes contribute insignificant amounts of rRNA in the grasshopper Eyprepocnemis plorans. AU - Ruiz-Estévez,Mercedes, AU - Badisco,Liesbeth, AU - Broeck,Jozef Vanden, AU - Perfectti,Francisco, AU - López-León,María Dolores, AU - Cabrero,Josefa, AU - Camacho,Juan Pedro M, Y1 - 2014/07/05/ PY - 2014/01/20/received PY - 2014/06/14/accepted PY - 2014/7/6/entrez PY - 2014/7/6/pubmed PY - 2015/1/22/medline SP - 1209 EP - 16 JF - Molecular genetics and genomics : MGG JO - Mol Genet Genomics VL - 289 IS - 6 N2 - The genetic inertness of supernumerary (B) chromosomes has recently been called into question after finding several cases of gene activity on them. The grasshopper Eyprepocnemis plorans harbors B chromosomes containing large amounts of ribosomal DNA (rDNA) units, some of which are eventually active, but the amount of rRNA transcripts contributed by B chromosomes, compared to those of the standard (A) chromosomes, is unknown. Here, we address this question by means of quantitative PCR (qPCR) for two different ITS2 amplicons, one coming from rDNA units located in both A and B chromosomes (ITS2(A+B)) and the other being specific to B chromosomes (ITS2(B)). We analyzed six body parts in nine males showing rDNA expression in their B chromosomes in the testis. Amplification of the ITS2(B) amplicon was successful in RNA extracted from all six body parts analyzed, but showed relative quantification (RQ) values four orders of magnitude lower than those obtained for the ITS(A+B) amplicon. RQ values differed significantly between body parts for the two amplicons, with testis, accessory gland and wing muscle showing threefold higher values than head, gastric cecum and hind leg. We conclude that the level of B-specific rDNA expression is extremely low even in individuals where B chromosome rDNA is not completely silenced. Bearing in mind that B chromosomes carry the largest rDNA cluster in the E. plorans genome, we also infer that the relative contribution of B chromosome rRNA genes to ribosome biogenesis is insignificant, at least in the body parts analyzed. SN - 1617-4623 UR - https://www.unboundmedicine.com/medline/citation/24997085/B_chromosomes_showing_active_ribosomal_RNA_genes_contribute_insignificant_amounts_of_rRNA_in_the_grasshopper_Eyprepocnemis_plorans_ L2 - https://doi.org/10.1007/s00438-014-0880-y DB - PRIME DP - Unbound Medicine ER -