TY  - JOUR
A1  - Liu, Ruiqi
A1  - Friedrich, Mike
A1  - Hemmen, Katherina
A1  - Jansen, Kerstin
A1  - Adolfi, Mateus C.
A1  - Schartl, Manfred
A1  - Heinze, Katrin G.
T1  - Dimerization of melanocortin 4 receptor controls puberty onset and body size polymorphism
JF  - Frontiers in Endocrinology
N2  - Xiphophorus fish exhibit a clear phenotypic polymorphism in puberty onset and reproductive strategies of males. In X. nigrensis and X. multilineatus, puberty onset is genetically determined and linked to a melanocortin 4 receptor (Mc4r) polymorphism of wild-type and mutant alleles on the sex chromosomes. We hypothesized that Mc4r mutant alleles act on wild-type alleles by a dominant negative effect through receptor dimerization, leading to differential intracellular signaling and effector gene activation. Depending on signaling strength, the onset of puberty either occurs early or is delayed. Here, we show by Förster Resonance Energy Transfer (FRET) that wild-type Xiphophorus Mc4r monomers can form homodimers, but also heterodimers with mutant receptors resulting in compromised signaling which explains the reduced Mc4r signaling in large males. Thus, hetero- vs. homo- dimerization seems to be the key molecular mechanism for the polymorphism in puberty onset and body size in male fish.
KW  - fluorescence lifetime imaging microscopy
KW  - Förster Resonance Energy Transfer
KW  - Mc4r
KW  - puberty
KW  - Xiphophorus
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-354261
SN  - 1664-2392
VL  - 14
ER  - 
TY  - JOUR
A1  - Sendell-Price, Ashley T.
A1  - Tulenko, Frank J.
A1  - Pettersson, Mats
A1  - Kang, Du
A1  - Montandon, Margo
A1  - Winkler, Sylke
A1  - Kulb, Kathleen
A1  - Naylor, Gavin P.
A1  - Phillippy, Adam
A1  - Fedrigo, Olivier
A1  - Mountcastle, Jacquelyn
A1  - Balacco, Jennifer R.
A1  - Dutra, Amalia
A1  - Dale, Rebecca E.
A1  - Haase, Bettina
A1  - Jarvis, Erich D.
A1  - Myers, Gene
A1  - Burgess, Shawn M.
A1  - Currie, Peter D.
A1  - Andersson, Leif
A1  - Schartl, Manfred
T1  - Low mutation rate in epaulette sharks is consistent with a slow rate of evolution in sharks
JF  - Nature Communications
N2  - Sharks occupy diverse ecological niches and play critical roles in marine ecosystems, often acting as apex predators. They are considered a slow-evolving lineage and have been suggested to exhibit exceptionally low cancer rates. These two features could be explained by a low nuclear mutation rate. Here, we provide a direct estimate of the nuclear mutation rate in the epaulette shark (Hemiscyllium ocellatum). We generate a high-quality reference genome, and resequence the whole genomes of parents and nine offspring to detect de novo mutations. Using stringent criteria, we estimate a mutation rate of 7×10\(^{−10}\) per base pair, per generation. This represents one of the lowest directly estimated mutation rates for any vertebrate clade, indicating that this basal vertebrate group is indeed a slowly evolving lineage whose ability to restore genetic diversity following a sustained population bottleneck may be hampered by a low mutation rate.
KW  - evolutionary genetics
KW  - genomics
KW  - molecular evolution
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357827
VL  - 14
ER  -