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Seroussi E, Pitel F, Leroux S, Morisson M, Bornelöv S, Miyara S, Yosefi S, Cogburn LA, Burt DW, Anderson L, Friedman-Einat M. Mapping of leptin and its syntenic genes to chicken chromosome 1p. BMC Genet 2017; 18:77. [PMID: 28793857 PMCID: PMC5550943 DOI: 10.1186/s12863-017-0543-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 08/02/2017] [Indexed: 01/22/2023] Open
Abstract
Background Misidentification of the chicken leptin gene has hampered research of leptin signaling in this species for almost two decades. Recently, the genuine leptin gene with a GC-rich (~70%) repetitive-sequence content was identified in the chicken genome but without indicating its genomic position. This suggests that such GC-rich sequences are difficult to sequence and therefore substantial regions are missing from the current chicken genome assembly. Results A radiation hybrid panel of chicken-hamster Wg3hCl2 cells was used to map the genome location of the chicken leptin gene. Contrary to our expectations, based on comparative genome mapping and sequence characteristics, the chicken leptin was not located on a microchromosome, which are known to contain GC-rich and repetitive regions, but at the distal tip of the largest chromosome (1p). Following conserved synteny with other vertebrates, we also mapped five additional genes to this genomic region (ARF5, SND1, LRRC4, RBM28, and FLNC), bridging the genomic gap in the current Galgal5 build for this chromosome region. All of the short scaffolds containing these genes were found to consist of GC-rich (54 to 65%) sequences comparing to the average GC-content of 40% on chromosome 1. In this syntenic group, the RNA-binding protein 28 (RBM28) was in closest proximity to leptin. We deduced the full-length of the RBM28 cDNA sequence and profiled its expression patterns detecting a negative correlation (R = − 0.7) between the expression of leptin and of RBM28 across tissues that expressed at least one of the genes above the average level. This observation suggested a local regulatory interaction between these genes. In adipose tissues, we observed a significant increase in RBM28 mRNA expression in breeds with lean phenotypes. Conclusion Mapping chicken leptin together with a cluster of five syntenic genes provided the final proof for its identification as the true chicken ortholog. The high GC-content observed for the chicken leptin syntenic group suggests that other similar clusters of genes in GC-rich genomic regions are missing from the current genome assembly (Galgal5), which should be resolved in future assemblies of the chicken genome. Electronic supplementary material The online version of this article (doi:10.1186/s12863-017-0543-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Eyal Seroussi
- Department of Animal Science, Agricultural Research Organization, Volcani Center, P.O. Box 15159, 7528809, Rishon LeTsiyon, Israel.
| | - Frédérique Pitel
- GenPhySE, Université de Toulouse, INRA, INPT, ENVT, 31326, Castanet Tolosan, France
| | - Sophie Leroux
- GenPhySE, Université de Toulouse, INRA, INPT, ENVT, 31326, Castanet Tolosan, France
| | - Mireille Morisson
- GenPhySE, Université de Toulouse, INRA, INPT, ENVT, 31326, Castanet Tolosan, France
| | - Susanne Bornelöv
- Department of Medical Biochemistry and Microbiology, Uppsala University, SE-75123, Uppsala, Sweden
| | - Shoval Miyara
- Department of Animal Science, Agricultural Research Organization, Volcani Center, P.O. Box 15159, 7528809, Rishon LeTsiyon, Israel
| | - Sara Yosefi
- Department of Animal Science, Agricultural Research Organization, Volcani Center, P.O. Box 15159, 7528809, Rishon LeTsiyon, Israel
| | - Larry A Cogburn
- Department of Animal and Food Sciences, University of Delaware, Newark, DE 19716, USA
| | - David W Burt
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Leif Anderson
- Department of Medical Biochemistry and Microbiology, Uppsala University, SE-75123, Uppsala, Sweden.,Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4458, USA.,Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, SE-75007, Uppsala, Sweden
| | - Miriam Friedman-Einat
- Department of Animal Science, Agricultural Research Organization, Volcani Center, P.O. Box 15159, 7528809, Rishon LeTsiyon, Israel.
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