Cloning and sequence analysis of FSH and LH in the giant panda (Ailuropoda melanoleuca)

Comparative Analysis of Gut Microbiota Among the Male, Female and Pregnant Giant Pandas (Ailuropoda Melanoleuca)

The giant panda (GP) was the most endangered species in China, and gut microbiota plays a vital role in host health. To determine the differences of the gut microbiota among the male, female and pregnant GPs, a comparative analysis of gut microbiota in GPs was carried out by 16S rRNA and ITS high-throughput sequencing. In 16S rRNA sequencing, 435 OTUs, 17 phyla and 182 genera were totally detected. Firmicutes (53.6%) was the predominant phylum followed by Proteobacteria (37.8%) and Fusobacteria (7.1%). Escherichia/Shigella (35.9%) was the most prevalent genus followed by Streptococcus (25.9%) and Clostridium (11.1%). In ITS sequencing, 920 OTUs, 6 phyla and 322 genera were also detected. Ascomycota (71.3%) was the predominant phylum followed by Basidiomycota (28.4%) and Zygomycota (0.15%). Purpureocillium (4.4%) was the most prevalent genus followed by Cladosporium (2.5%) and Pezicula (2.4%). Comparative analysis indicated that the male GPs harbor a higher abundance of phylum Firmicutes than female GPs with the contribution from genus Streptococcus. Meanwhile, the female GPs harbor a higher abundance of phylum Proteobacteria than male GPs with the contribution from genus Escherichia/ Shigella. In addition, the shift in bacteria from female to pregnant GPs indicated that phylum Firmicutes increased significantly with the contribution from Clostridium in the gut, which may provide an opportunity to study possible associations with low reproduction of the GPs.

Urinary profiles of luteinizing hormone, estrogen and progestagen during the estrous and gestational periods in giant pandas (Ailuropda melanoleuca)

Luteinizing hormone (LH) is one of the main pituitary hormones that regulate ovulation, however its role has not been studied in giant panda. In this study, we developed an ELISA method for the detection of panda urinary LH. We analyzed urinary hormones of 24 female pandas during 36 breeding periods, we found females could easily be impregnated if the first mating occurred within 10 hours after LH peak. We also found the patterns of the ratios of urinary LH and progestagen in pandas that bred and successfully gave birth were significantly different from those that bred but failed to give birth. These data was the first to provide the urinary LH profiles during the estrous and gestational periods in pandas, and demonstrated that the appearance of the urinary LH peak indicated the timing of ovulation. The LH detection together with estrogen analysis makes the window for successful mating narrower than previously reported. Moreover, detection of urinary LH and progestagen can be used to discriminate between pregnancies and pseudopregnancies/miscarriages in the species. Thus, our findings suggest that LH not only plays a critical role in regulating ovulation but also plays an important role in maintaining pregnancy in the giant panda.

Comparative analysis and molecular characterization of a gene BANF1 encoded a DNA-binding protein during mitosis from the Giant Panda and Black Bear

Barrier to autointegration factor 1 (BANF1) is a DNA-binding protein found in the nucleus and cytoplasm of eukaryotic cells that functions to establish nuclear architecture during mitosis. The cDNA and the genomic sequence of BANF1 were cloned from the Giant Panda (Ailuropoda melanoleuca) and Black Bear (Ursus thibetanus mupinensis) using RT-PCR technology and Touchdown-PCR, respectively. The cDNA of the BANF1 cloned from Giant Panda and Black Bear is 297 bp in size, containing an open reading frame of 270 bp encoding 89 amino acids. The length of the genomic sequence from Giant Panda is 521 bp, from Black Bear is 536 bp, which were found both to possess 2 exons. Alignment analysis indicated that the nucleotide sequence and the deduced amino acid sequence are highly conserved to some mammalian species studied. Topology prediction showed there is one Protein kinase C phosphorylation site, one Casein kinase II phosphorylation site, one Tyrosine kinase phosphorylation site, one N-myristoylation site, and one Amidation site in the BANF1 protein of the Giant Panda, and there is one Protein kinase C phosphorylation site, one Tyrosine kinase phosphorylation site, one N-myristoylation site, and one Amidation site in the BANF1 protein of the Black Bear. The BANF1 gene can be readily expressed in E. coli. Results showed that the protein BANF1 fusion with the N-terminally His-tagged form gave rise to the accumulation of an expected 14 kD polypeptide that formed inclusion bodies. The expression products obtained could be used to purify the proteins and study their function further.

Molecular characterization of the Chinese alligator follicle-stimulating hormone β subunit (FSHβ) and its expression during the female reproductive cycle

The Chinese alligator Alligator sinensis is an endangered species endemic to China, it has a highly specialized reproductive pattern with low fecundity. Up to date, little is known about the regulation of its female reproductive cycle. Follicle-stimulating hormone (FSH), a glycoprotein hormone, plays a key role in stimulating and regulating ovarian follicular development and egg production. In this study, the complete FSHβ cDNA from the ovary of the Chinese alligator was obtained for the first time, it consists of 843-bp nucleotides, including 120-bp nucleotides of the 5'-untranslated region (UTR), 396-bp of the open reading frame, and 3'-UTR of 327-bp nucleotides. It encodes a 131-amino acid precursor molecule of FSHβ with a signal peptide of 18 amino acids followed by a mature protein of 113 amino acids. Its deduced amino acid sequence shares high identities with the American alligator (100%) and birds (89-92%). Phylogenetic tree analysis of the FSHβ amino acid sequence indicated that alligators cluster into the bird branch. Tissue distribution analyses indicated that FSHβ mRNA is expressed in ovary, intestine and liver with the highest level in the ovary, while not in stomach, pancreas, heart, thymus and thyroid. Expression of FSHβ in ovary increases in May (breeding prophase) and peaks in July (breeding period), it is maintained at high levels through September, then decreases significantly in November (post-reproductive period) and remains relatively low from January to March (hibernating period). These temporal changes of FSHβ expression implicated that it might play an important role in promoting ovarian development during the female reproductive cycle.

Cloning, Characterization and Tissue Specific Expression of Amur Tiger (Panthera tigris altaica) IGF-I

Insulin-like growth factor I (IGF-I) plays an important role in regulating gonad function, which is essential for normal reproduction in animals, especially in sexual receptivity and reproductive behavior. In this study, a cDNA encoding Amur tiger (Panthera tigris altaica) IGF-I was isolated from liver total RNA using RT-PCR. The IGF-I cDNA of Amur tiger (ATIGF-I) was highly homologous to that of other animals, 84.8% to rat, 93.7% to human and horse. Alignment analysis showed that the cysteine residues and many amino acid residues of putative mature ATIGF-I are highly conserved in mammalian species, confirming the high sequence homology observed in other species. DNA encoding the mature ATIGF-I peptide was ligated with pET-DsbA expression vector and highly expressed in Escherichia coli BL21 with IPTG induction. The recombinant proteins expressed existed mostly in the soluble protein fraction, and were purified with metal affinity resins. Western blotting confirmed that the recombinant proteins reacted with antibodies against IGF-I. The results obtained here should be useful for large-scale production of biological active ATIGF-I protein, as well as for further research on growth, development, and reproduction in the Amur tiger. Tissue specific expression of ATIGF-I mRNA in the Amur tiger was examined by reverse transcription-polymerase chain reaction (RT-PCR), The major ATIGF-I mRNA expression tissue was the liver, while medium signals were found in the uterus, ovary, and pituitary, and minor signals were detected in various tissues including the heart, spleen, pancreas, and kidney. The results indicate that IGF-I might play an important role in the reproductive system and in cub development in the Amur tiger.

Overexpression, purification, molecular characterization and pharmacological evaluation for anticancer activity of ribosomal protein S23 from the giant panda (Ailuropoda melanoleuca)

Ribosomal protein S23 (RPS23) is a component of the 40S small ribosomal subunit encoded by the RPS23 gene, which is specific to eukaryotes. The cDNA and genomic sequence of RPS23 were cloned from Ailuropoda melanoleuca (A. melanoleuca) using reverse transcription‑polymerase chain reaction (RT-PCR) technology and touchdown PCR, respectively. The two sequences were analyzed preliminarily and the cDNA of the RPS23 gene was overexpressed in Escherichia coli (E. coli) BL21. The cDNA of RPS23 cloned from giant panda was 472 bp, and it contained an open reading frame (ORF) of 432 bp encoding 142 amino acids. The nucleotide sequence of the coding sequence showed a high degree of homology to some mammals as determined by BLAST analysis, similar to the amino acid sequence. The genomic sequence was 2,105 bp in length, with 4 exons and 3 introns. The primary structure analysis revealed that the molecular weight of the putative RPS23 protein was 15.80 kDa with a theoretical isoelectric point (pI) of 11.23. The molecular weight of the recombinant protein RPS23 was 21.5 kDa with a theoretical pI of 10.57. Topology prediction showed that there are seven different patterns of functional sites in the RPS23 protein of giant panda. RPS23 was successfully expressed in E. coli and its protein fused with the N‑terminal His‑tagged protein triggered the accumulation of an expected 21.5‑kDa polypeptide. The inhibitory rate of tumor growth in mice treated with 0.1 µg/ml RPS23 protein was 49.45%, the highest in the three doses used, which may be comparable to mannatide treatment. Histology of immune organs showed that the tissues were characterized by a regular and tight arrangement, while tumor tissues of the mice in the RPS23 group exhibited a loose arrangement compared to the control group. However, there was no obvious damage to other organs, such as the heart, lung and kidney. Investigations are currently being conducted to determine the bioactive principles of the recombinant protein RPS23 responsible for its anticancer activity.

cDNA, genomic sequence cloning and overexpression of giant panda (Ailuropoda melanoleuca) mitochondrial ATP synthase ATP5G1

The ATP5G1 gene is one of the three genes that encode mitochondrial ATP synthase subunit c of the proton channel. We cloned the cDNA and determined the genomic sequence of the ATP5G1 gene from the giant panda (Ailuropoda melanoleuca) using RT-PCR technology and touchdown-PCR, respectively. The cloned cDNA fragment contains an open reading frame of 411 bp encoding 136 amino acids; the length of the genomic sequence is of 1838 bp, containing three exons and two introns. Alignment analysis revealed that the nucleotide sequence and the deduced protein sequence are highly conserved compared to Homo sapiens, Mus musculus, Rattus norvegicus, Bos taurus, and Sus scrofa. The homologies for nucleotide sequences of the giant panda ATP5G1 to those of these species are 93.92, 92.21, 92.46, 93.67, and 92.46%, respectively, and the homologies for amino acid sequences are 90.44, 95.59, 93.38, 94.12, and 91.91%, respectively. Topology prediction showed that there is one protein kinase C phosphorylation site, one casein kinase II phosphorylation site, five N-myristoylation sites, and one ATP synthase c subunit signature in the ATP5G1 protein of the giant panda. The cDNA of ATP5G1 was transfected into Escherichia coli, and the ATP5G1 fused with the N-terminally GST-tagged protein gave rise to accumulation of an expected 40-kDa polypeptide, which had the characteristics of the predicted protein.

MOLECULAR CLONING, SEQUENCING, EXPRESSION AND BIOLOGICAL ACTIVITY OF GIANT PANDA (AILUROPODA MELANOLEUCA) INTERFERON-GAMMA

The giant panda (Ailuropoda melanoleuca) is an endangered species and indigenous to China. Interferon-gamma (IFN-γ) is the only member of type □ IFN and is vital for the regulation of host adapted immunity and inflammatory response. Little is known aboutthe FN-γ gene and its roles in giant panda.In this study, IFN-γ gene of Qinling giant panda was amplified from total blood RNA by RT-CPR, cloned, sequenced and analysed. The open reading frame (ORF) of Qinling giant panda IFN-γ encodes 152 amino acidsand is highly similar to Sichuan giant panda with an identity of 99.3% in cDNA sequence. The IFN-γ cDNA sequence was ligated to the pET32a vector and transformed into E. coli BL21 competent cells. Expression of recombinant IFN-γ protein of Qinling giant panda in E. coli was confirmed by SDS-PAGE and Western blot analysis. Biological activity assay indicated that the recombinant IFN-γ protein at the concentration of 4-10 µg/ml activated the giant panda peripheral blood lymphocytes,while at 12 µg/mlinhibited. the activation of the lymphocytes.These findings provide insights into the evolution of giant panda IFN-γ and information regarding amino acid residues essential for their biological activity.

cDNA cloning, overexpression, purification and pharmacologic evaluation for anticancer activity of ribosomal protein L23A gene (RPL23A) from the Giant Panda

RPL23A gene encodes a ribosomal protein that is a component of the 60S subunit. The protein belongs to the L23P family of ribosomal proteins, which is located in the cytoplasm. The purpose of this paper was to explore the structure and anti-cancer function of ribosomal protein L23A (RPL23A) gene of the Giant Panda (Ailuropoda melanoleuca). The cDNA of RPL23A was cloned successfully from the Giant Panda using RT-PCR technology. We constructed a recombinant expression vector containing RPL23A cDNA and over-expressed it in Escherichia coli using pET28a plasmids. The expression product obtained was purified by using Ni chelating affinity chromatography. Recombinant protein of RPL23A obtained from the experiment acted on Hep-2 cells and human HepG-2 cells, then the growth inhibitory effect of these cells was observed by MTT (3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2H-tetrazolium bromide) assay. The result indicated that the length of the fragment cloned is 506 bp, and it contains an open-reading frame (ORF) of 471 bp encoding 156 amino acids. Primary structure analysis revealed that the molecular weight of the putative RPL23A protein is 17.719 kDa with a theoretical pI 11.16. The molecular weight of the recombinant protein RPL23A is 21.265 kDa with a theoretical pI 10.57. The RPL23A gene can be really expressed in E. coli and the RPL23A protein, fusioned with the N-terminally His-tagged protein, gave rise to the accumulation of an expected 22 KDa polypeptide. The data showed that the recombinant protein RPL23A had a time- and dose-dependency on the cell growth inhibition rate. The data also indicated that the effect at low concentrations was better than at high concentrations on Hep-2 cells, and that the concentration of 0.185 μg/mL had the best rate of growth inhibition of 36.31%. All results of the experiment revealed that the recombinant protein RPL23A exhibited anti-cancer function on the Hep-2 cells. The study provides a scientific basis and aids orientation for the research and development of cancer protein drugs as well as possible anti-cancer mechanisms. Further research is on going to determine the bioactive principle(s) of recombinant protein RPL23A responsible for its anticancer activity.

cDNA, genomic sequence cloning, and overexpression of EIF1 from the giant panda (Ailuropoda Melanoleuca) and the black bear (Ursus Thibetanus Mupinensis)

Eukaryotic initiation factor (eIF) EIF1 is a universally conserved translation factor that is involved in translation initiation site selection. The cDNA and the genomic sequences of EIF1 were cloned successfully from the giant panda (Ailuropoda melanoleuca) and the black bear (Ursus thibetanus mupinensis) using reverse transcription polymerase chain reaction (RT-PCR) technology and touchdown-polymerase chain reaction, respectively. The cDNAs of the EIF1 cloned from the giant panda and the black bear are 418 bp in size, containing an open reading frame (ORF) of 342 bp encoding 113 amino acids. The length of the genomic sequence of the giant panda is 1909 bp, which contains four exons and three introns. The length of the genomic sequence of the black bear is 1897 bp, which also contains four exons and three introns. Sequence alignment indicates a high degree of homology to those of Homo sapiens, Mus musculus, Rattus norvegicus, and Bos Taurus at both amino acid and DNA levels. Topology prediction shows there are one N-glycosylation site, two Casein kinase II phosphorylation sites, and a Amidation site in the EIF1 protein of the giant panda and black bear. In addition, there is a protein kinase C phosphorylation site in EIF1 of the giant panda. The giant panda and the black bear EIF1 genes were overexpressed in E. coli BL21. The results indicated that the both EIF1 fusion proteins with the N-terminally His-tagged form gave rise to the accumulation of two expected 19 kDa polypeptide. The expression products obtained could be used to purify the proteins and study their function further.

cDNA, genomic sequence and overexpression of crystallin alpha-B Gene (CRYAB) of the Giant Panda

AlphaB-crystallin, a small heat-shock protein, has been shown to prevent the aggregation of other proteins under various stress conditions. Here we have cloned the cDNA and the genomic sequence of CRYAB gene from the Giant Panda (Ailuropoda melanoleuca) using RT-PCR technology and Touchdown-PCR, respectively. The length of cDNA fragment cloned contains an open reading frame of 528bp encoding 175 amino acids and the length of the genomic sequence is 3189bp, containing three exons and two introns. Alignment analysis indicated that the nucleotide sequence and the deduced amino acid sequence are highly conserved to other four species studied, including Homo sapiens, Mus musculus, Rattus norvegicus and Bos taurus. The homologies for nucleotide sequences of Giant Panda CRYAB to that of these species are 93.9%, 91.5%, 91.5% and 95.3%, respectively, and the homologies for amino acid sequences are 98.3%, 97.1%,97.7% and 99.4%, respectively. Topology prediction shows that there are only four Casein kinase II phosphorylation sites in the CRYAB protein of the Giant Panda. The cDNA of CRYAB was transfected into E. coli, and the CRYAB fused with the N-terminally His-tagged protein gave rise to the accumulation of an expected 24KDa polypeptide, which accorded with the predicted protein. The expression product obtained could be used for purification and study of its function further.

cDNA cloning and overexpression of acidic ribosomal phosphoprotein P1 gene (RPLP1) from the giant panda

RPLP1 is one of acidic ribosomal phosphoproteins encoded by RPLP1 gene, which plays an important role in the elongation step of protein synthesis. The cDNA of RPLP1 was cloned successfully for the first time from the Giant Panda (Ailuropoda melanoleuca) using RT-PCR technology, which was also sequenced, analyzed preliminarily and expressed in E.coli. The cDNA fragment cloned is 449bp in size, containing an open reading frame of 344bp encoding 114 amino acids. Alignment analysis indicated that the nucleotide sequence and the deduced amino acid sequence are highly conserved to other five species studied, including Homo sapiens, Mus musculus, Rattus norvegicus, Bos Taurus and Sus scrofa. The homologies for nucleotide sequences of Giant Panda PPLP1 to that of these species are 92.4%, 89.8%, 89.0%, 91.3% and 87.5%, while the homologies for amino acid sequences are 96.5%, 94.7%, 95.6%, 96.5% and 88.6%. Topology prediction showed there are three Casein kinase II phosphorylation sites and two N-myristoylation sites in the RPLP1 protein of the Giant Panda (Ailuropoda melanoleuca). The RPLP1 gene was overexpressed in E. coli and the result indicated that RPLP1 fusion with the N-terminally His-tagged form gave rise to the accumulation of an expected 18kDa polypeptide, which was in accordance with the predicted protein and could also be used to purify the protein and study its function.

Molecular cloning and histological localization of LH-like substances in a bottlenose dolphin (Tursiops truncatus) placenta

All mammals exhibit pituitary-specific expression of LH and FSH, whereas placental expression of gonadotropins has been reported only in primates and equids. Some cetaceans, such as dolphins, have a long gestational period and a sexual cycle of about 27 days almost comparable with that of humans. Histologically, dolphins have an epitheliochorial placentae that resembles placentas of Perissodactyla including horses. In the present study, we cloned cDNAs encoding gonadotropins and observed their immunohistochemical localization in the placenta of bottlenose dolphin. The cDNAs obtained encoded 120 amino acids for the alpha-subunit (including 96 amino acids of mature proteins), and 141 amino acids for the beta-subunit (including 121 amino acids of mature proteins). The sequence of the alpha-subunit was similar to that in the pig (Artiodactyla) pituitary glycoprotein hormone [96.7% homology at amino acids (aa) level], and the sequence of the beta-subunit was similar to that of luteinizing hormone (LH) in the pig [94.3% homology at aa level] and white rhinoceros (Perissodactyla) [93.3% homology at aa level]. Of interest, dolphin LHbeta lacks carboxyl-terminal-peptides (CTP). This fact suggests that CTP are not essential for placental expression of gonadotropin in dolphins. Immunohistochemical observations employing anti-ovine LHbeta antibody revealed positive staining in the villositycal tissue. Our observations suggest placental expression of gonadotropin homologues in cetaceans and possible evolutionary conservation of placentae-derived hormonal control of ovarian functions during pregnancy.

New technologies for the study of carnivore reproduction

Routine analysis of urinary metabolites of estrogen and progesterone provided substantial information about the estrous cycle of bears. However, these data alone were not adequate to determine the precise timing of ovulation needed to maximize AI success rates, or to distinguish between pregnancy and pseudopregnancy. Therefore, there is a critical need to develop technologies that will enhance understanding of the reproductive mechanisms of ursids. Using the domestic dog as a model, three techniques were investigated for potential application to the propagation of captive endangered bears. In a modification of standard staining of bitch vaginal cells, trichrome staining of giant panda cells revealed two consistent chromic shifts 9 and 2 days prior to the periovulatory decrease in urinary estrone sulfate, enhancing the ability to predict ovarian events preceding ovulation. To further define the relationship between the decrease in estrogen and ovulation, the utility of a rapid immunochromatographic LH assay was investigated for giant pandas using a commercial LH kit canine serum. Serum collected during estrus exhibited positive test results, indicating the cross-reactivity of giant panda LH with canine LH antibodies, and preliminary data supported further development of the LH kit for the detection of LH in bear urine. Due to the limitations of hormone analysis for distinguishing pregnancy from pseudopregnancy in canids and ursids, forward-looking infrared thermography was evaluated as a method to visualize proliferating placental tissue, fetuses, or both. While further investigation is needed to confirm the utility of thermal imaging for pregnancy diagnosis in the domestic bitch, pregnancy and pseudopregnancy were successfully detected in two giant pandas.

Molecular cloning of follicle-stimulating hormone (FSH)-beta subunit cDNA from duck pituitary

We have cloned FSH-beta cDNA from duck pituitary gland by reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA end (RACE) methods. The cloned duck FSH-beta cDNA contains 1909-bp nucleotides including 396-bp of open-reading frame and 1491-bp of 3'-untranslational region. The open-reading frame encodes a 131-amino acid protein with a putative 20-amino acid signal peptide and a putative 111-amino acid mature protein. The deduced amino acid sequence shows a remarkable similarity (94-98%) to those of other avian FSH-beta subunits; while it exhibits lower similarities with those of turtles (82-84%), mammals (63-71%), and amphibians (53-57%). The structural model analysis of duck FSH suggests that the cysteine-knot and beta-strands for maintaining the specific structural frame, and the "seat-belt" loop for specific binding to FSH receptor have been conserved in tetrapodian FSH-betas.

Molecular cloning of the cDNA encoding follicle-stimulating hormone beta subunit of the Chinese soft-shell turtle Pelodiscus sinensis, and its gene expression

Follicle-stimulating hormone (FSH) is a member of the pituitary glycoprotein hormone family. These hormones are composed of two dissimilar subunits, alpha and beta. Very little information is available regarding the nucleotide and amino acid sequence of FSHbeta in reptilian species. For better understanding of the phylogenetic diversity and evolution of FSH molecule, we have isolated and sequenced the complementary DNA (cDNA) encoding the Chinese soft-shell turtle (Pelodiscus sinensis, Family of Trionychidae) FSHbeta precursor molecule by reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA end (RACE) methods. The cloned Chinese soft-shell turtle FSHbeta cDNA consists of 602-bp nucleotides, including 34-bp nucleotides of the 5'-untranslated region (UTR), 396-bp of the open reading frame, and 3'-UTR of 206-bp nucleotides. It encodes a 131-amino acid precursor molecule of FSHbeta subunit with a signal peptide of 20 amino acids followed by a mature protein of 111 amino acids. Twelve cysteine residues, forming six disulfide bonds within beta-subunit and two putative asparagine-linked glycosylation sites, are also conserved in the Chinese soft-shell turtle FSHbeta subunit. The deduced amino acid sequence of the Chinese soft-shell turtle FSHbeta shares identities of 97% with Reeves's turtle (Family of Bataguridae), 83-89% with birds, 61-70% with mammals, 63-66% with amphibians and 40-58% with fish. By contrast, when comparing the FSHbeta with the beta-subunits of the Chinese soft-shell turtle luteinizing hormone and thyroid stimulating hormone, the homologies are as low as 38 and 39%, respectively. A phylogenetic tree including reptilian species of FSHbeta subunits, is presented for the first time. Out of various tissues examined, FSHbeta mRNA was only expressed in the pituitary gland and can be up-regulated by gonadotropin-releasing hormone in pituitary tissue culture as estimated by fluorescence real-time PCR analysis.

Molecular Cloning of Giant Panda Pituitary Prolactin cDNA and Its Expression in Escherichia coli

cDNA encoding pituitary (PRL) of giant panda was obtained using RT-PCR and expressed in E. coli. The results revealed that panda PRL cDNA encodes a precursor protein of 229 amino acids including a putative signal peptide of 30 amino acids and a mature protein of 199 residues with one potential N-glycosylation site. Sequence comparison indicated that panda PRL shares a high degree of identity to other known PRL sequences ranging from 98% with mink PRL to about 50% with rodent PRL. Six cysteine residues and 29 conserved residues distributed in four domains (PD1, PD2, PD3, and PD4) of PRL were observed. through multiple sequence alignment. Fourteen key residues of binding sites 1 and 2 involved in receptor binding are conserved in panda PRL. GST fused recombinant panda PRL protein was efficiently expressed with the form of insoluble inclusion bodies in E. coli BL21 transformed with a pGEX-4T-1 expression vector containing the DNA sequence encoding mature panda PRL. Western blot analysis indicated that GST-panda PRL recombinant protein could be recognized by antibody against human PRL. Our results would contribute to further elucidating the structural and functional characteristics of pituitary PRL and provide a basis for the production of recombinant panda prolactin for future use in the breeding of giant panda.