1022-7954/05/4107- © 2005 Pleiades Publishing, Inc.
Russian Journal of Genetics, Vol. 41, No. 7, 2005, pp. 755–759. From Genetika, Vol. 41, No. 7, 2005, pp. 925–930.
Original English Text Copyright © 2005 by Jifang Zheng, Bi Hu, Duansheng Wu.
Recently, a novel family of DNA-binding proteins
has been described that is characterized by the presence
of a conserved DNA-binding domain: the High Mobil-
ity Group (HMG) box . The HMG-box is a con-
served 79-amino-acid domain present in two copies the
canonical HMG1 protein . HMG1 protein is the
abundant nonhistone chromosomal protein in eukary-
otic cell. It binds preferentially to non-B-DNA, as cru-
ciform , 4-way junction [4, 5], cisplatin-modiﬁed
DNA  and nicked-circular DNA . Although their
exact functions have yet to be elucidated, HMG1 pro-
teins are implicated in such diverse events as DNA rep-
lication , DNA recombination , nucleosome
assembly  and transcription [9, 10].
Cloning and sequencing
cDNA from differ-
ent species could be useful to understand the way in
which HMG1 protein interacts with DNA, molecular
and other unknown functions of HMG1 protein.
Human , mouse , Chinese hamster , rat
, bovine , pig , chicken  and rainbow
cDNAs have been cloned. However,
sequence information for reptilian
gene is not
yet available. Only is information provided by the fact
that total RNAs from turtle testis and kidney were
reacted with the human
cDNA probe by North-
ern blot . In this paper, we have isolated and
sequenced a cDNA that encodes HMG1 protein from
the Chinese soft-shell turtle (
Amino acid sequences of turtle HMG1 protein were
compared with other known examples.
MATERIALS AND METHODS
Animal and isolation of total RNA.
An individual of
was obtained from a commercial
supplier. Total RNA was isolated from fresh kidney tis-
sue ground in liquid nitrogen using TRIZOL reagent
(Gibco-BRL) according to the manufacturer’s protocol.
Total RNA was dissolved in 0.1% DEPC-treated water
and stored at –70
C until use.
Reverse transcription and PCR (RT–PCR) ampliﬁ-
For reverse transcription and PCR ampliﬁca-
tion, the attention was paid to the nucleotide sequences
in the 5' UTR neighboring ATG start site and in the 3'
UTR neighboring TAA termination signal of chicken
cDNAs . The following oligonucleotide
primers (forward primer: 5'-CAGTACAGAGTCAA-
GATGGC-3'; reverse primer: 5'-GCACGTAGCTAGC
TTAGATGAC-3') were designed and subjected to RT–
PCR ampliﬁcation. These primers were expected to
cDNA of about 680 bp.
Total RNA was reverse transcribed and subse-
quently PCR ampliﬁed using a TaKaRa RNA LA
kit, version 1.1 (Takara, Japan) according to the
suppliers’ recommendations. For reverse transcription,
total RNA and downstream primer (reverse primer)
were added to a reaction buffer containing 5 mM of
deoxynucleotide, 1 U/
l of RNase inhibitor, and
0.25 1 U/
l AMV reverse transcriptase. The reaction
mixture was incubated at 42
C for 30 min. After reverse
transcription, aliquots (2
l) of cDNA mixture were
Sequence of a cDNA Encoding Turtle
High Mobility Group 1 Protein*
, Bi Hu
, and Duansheng Wu
Institute of Cell and Genetics, College of Life Sciences and Technology, Nanhua University, Hengyang, 421001 China
Institue of Physiology, Medical College, Nanhua University, Hengyang, 421001 China; e-mail: email@example.com
Institute of Zoology, College of Life Sciences and Technology, Nanhua University, Hengyang, 421001 China
Received July 26, 2004; in ﬁnal form, February 16, 2005
—In order to understand sequence information about turtle
gene, a cDNA encoding HMG1
protein of the Chinese soft-shell turtle (
) was ampliﬁed by RT–PCR from kidney total RNA,
and was cloned, sequenced and analyzed. The results revealed that the open reading frame (ORF) of turtle
cDNA is 606 bp long. The ORF codiﬁes 202 amino acid residues, from which two DNA-binding
domains and one polyacidic region are derived. The DNA-binding domains share higher amino acid identity
with homologous sequences of chicken (96.5%) and mammals (74%) than homologous sequence of rainbow
trout (67%). The polyacidic region shows 84.6% amino acid homology with the equivalent region of chicken
cDNA. Turtle HMG1 protein contains 3 Cys residues located at completely conserved positions. Con-
servation in sequence and structure suggests that the functions of turtle
cDNA may be highly conserved
during evolution. To our knowledge, this is the ﬁrst report of
cDNA sequence in any reptilian.
* The text was submitted by the authors in English.