Vol. 61, 2022
Correlated Expression of the
Opsin Retrogene LWS-R and its Host Gene in Two Poeciliid Fishes
of Science Education, National Taipei University of Education, No.134,
Sec.2, Heping E. Rd., Da’an District, Taipei City 10671, Taiwan.
*Correspondence: E-mail: firstname.lastname@example.org (Chang). Tel.:
Received 4 August 2021 / Accepted 22
Communicated by John Wang
important role of retrogenes in genome evolution and species
differentiation is becoming increasingly accepted. One synapomorphy
among cyprinodontoid fish is a retrotransposed version of a
long-wavelength sensitive (LWS) opsin gene, LWS-R, within an intron of
the gephyrin (GPHN) gene. These two genes display opposing
orientations. It had been speculated that LWS-R hijacks the
cis-regulatory elements of GPHN for transcription, but whether their
expression is correlated had remained unclear. Here, in silico
predictions identified putative promoters upstream of the translation
start site of LWS-R, indicating that its transcription is driven by its
own promoter rather than by the GPHN promoter. However, consistent
expression ratios of LWS-R:GPHN in the eyeball and brain of fishes
that the respective gene transcriptions are correlated. Co-expression
is potentially modulated by histone exchange during GPHN transcription.
Two isoforms were detected in this study, i.e., intron-free and
intron-retaining. Intron-free LWS-R was only expressed in the eyeball
of fishes, whereas intron-retaining LWS-R occurred in both eyeball and
brain. Expression of vision-associated LWS-R beyond the eyeball
supports that it is co-expressed with more ubiquitous GPHN.
Key words: Retrotransposition,
Opsin, Promoter, Gephyrin, Histone exchange, Intron retention.
Citation: Chang CH. 2022. Correlated
expression of the opsin retrogene LWS-R and its host gene in two
poeciliid fishes. Zool Stud 61:16.
materials: Fig. S1