| Summary: | 碩士 === 國立臺灣大學 === 動物學系 === 86 === Abstract
Rod opsin, rhodopsin, is one of the photoreceptors but locates
at rod cells, which mediates dim-light vision. Only one type of
rhodopsin cDNA was reported in most of the species studied.
However, two types of rhodopsin cDNA were cloned from the common
carp (Cyprinus carpio). They shared 97.2% and 98.6% identities
of polynucleotide and amino acid sequences, respectively (Tsai
et al., 1994; Lim et al., 1997). Two types of rhodopsin genomic
genes were identified in the same individual via PCR and
restriction analysis. In addition, a genomic library of the
common carp was constructed and the genomic gene of type I
rhodopsin was isolated and sequenced. Compared to the type II
rhodopsin gene (Lim, 1996), the type I gene shared only 45.6%
identity of polynucleotide sequences in the upstream region
ranged from nucleotide (nt) position from -3426 to +101.
However, there were three conserved segments, which were at nt
-1252~ -602, -530~ -405 and -132~ +101, with 77.7%, 80.0% and
94.6% identities, respectively. And the two types of gene were
both intronless.
To define the cis-acting DNA elementsences upstream of the type
I rhodopsin gene fused to the GFP (green fluorescence protein)
cDNA as a reporter gene. Upstream sequences extending from -6k
to +74 bp, from -143 to +101 bp, and from -70 to +101 bp were
able to direct retinal-specific expression, while -46 to +101 bp
were not. This suggests that elements which regulate retinal-
specific expression may locate within -70~ -46.
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