Complete amino acid sequences of follitropin and lutropin in the ostrich, Struthio camelus

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.

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.

Sequence analysis of cDNA encoding rabbit follicle-stimulating hormone beta-subunit precursor protein

To understand the molecular basis of the rabbit's efficient superovulation, we determined the cDNA sequence of the follicle-stimulating hormone (FSH) beta-subunit precursor protein using a combination of 5'- and 3'-rapid amplification of cDNA ends (RACE) with pituitary cDNA libraries of the Japanese White rabbit and compared it with those of other mammals. RACE experiments detected at least three transcripts for the FSHbeta precursor protein in the libraries. The transcripts had lengths of 457, 1,621, and 1,767 bp, from the 5'-end to the poly(A) site. The shortest and mid-length transcripts had the putative polyadenylation signal sequence AATAAA at nucleotides 436 and 1,601, respectively, whereas the longest form had an ATTAAA sequence at nucleotide 1,745 of the cDNA sequence. These transcripts are likely to be polyadenylation variants of one large transcript because they share the same coding sequence for the precursor protein (130 amino acid residues in length). However, only a few shortest variants seem to be formed because the shortest variants were not detected by Northern blot analysis. Phylogenetic analysis of the deduced amino acid sequence indicates that the rabbit is phylogenetically closer to humans than to the other mammals, suggesting that an FSH preparation from human sources would be superior as a follicle stimulant for the induction of superovulation.

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.

Cloning of cDNAs encoding the three pituitary glycoprotein hormone beta subunit precursor molecules in the Japanese toad, Bufo japonicus

Complementary DNAs encoding precursor molecules of the beta subunits of three pituitary glycoprotein hormones (LH, FSH, and TSH) of the Japanese toad (Bufo japonicus) were isolated and sequenced. Unexpectedly large numbers of single nucleotide substitutions were found in all three beta subunit cDNAs. The eight isolated LH beta precursor cDNA clones were classified into six forms of nucleotide sequence, with four nucleotide substitutions each in the apoprotein coding region and in the 3' untranslated region (UTR). In the deduced amino acid sequence, the LH beta subunit showed two forms with a single amino acid substitution. The seven isolated FSH beta subunit cDNAs were classified into two forms, which differed from each other at 11 positions in the 3' UTR. The six isolated TSH beta subunit clones were classified into four forms with 2 and 5 nucleotide substitutions in the signal peptide and apoprotein coding regions, respectively. However, all the substitutions in the apoprotein coding region were silent. The substitution in the signal peptide coding region could produce three forms of signal peptide. Amino acid sequence comparison revealed that the toad LH beta subunit is more similar to the fish GTH II beta subunit than to mammalian and avian LH beta subunits. We found that the toad LH beta subunit molecule is a partial chimera of LH and FSH; amino acid residues located in 36th to 42nd and 96th to 99th are identical or similar to those of not LH- but FSH-beta subunit in mammalian, whereas it is more similar to LH- than FSH-beta subunit in total. We also found that the toad FSH beta subunit is more similar to the fish GTH II beta subunit than to the fish GTH I beta subunit and that the toad TSH beta subunit is more similar to tetrapod TSH beta subunits than to fish TSH beta subunits.

Cloning of the genes for the pituitary glycoprotein hormone alpha and follicle-stimulating hormone beta subunits in the Japanese crested ibis, Nipponia nippon

We have isolated a part of the gene for the pituitary glycoprotein hormone common alpha subunit (PGHalpha) and the whole gene for the follicle-stimulating hormone beta subunit (FSHbeta) in the Japanese crested ibis (Nipponia nippon), a critically endangered bird species in East Asia. The nucleotide sequence of a part of the PGHalpha gene (5026 bp) contained three exons holding the whole coding and 3' untranslated regions, but lacked a 5' untranslated region. Its exon-intron structure was similar to that in mammals, but different from that in teleosts in the location of the second intron. For the FSHbeta gene, the nucleotide sequence of 7633 bp was assembled from two phage clones. The exon-intron structure of three exons and two introns was similar to that observed in mammals and teleosts. In the putative promoter region of the ibis FSHbeta gene, a progesterone responsive element (PRE)-like sequence and two AP-1 responsive element-like sequences reported in the ovine FSHbeta gene were not conserved in complete form. The increased number of ATTTA motifs in the putative 3' untranslated region in comparison with those in Japanese quail and chicken FSHbeta cDNA suggested that more rapid degradation of FSHbeta mRNA occurs in this species. Deduced amino acid sequences of the ibis PGHalpha and FSHbeta showed high similarities with those of the corresponding subunits of other avian species. This is the first report on the genomic sequences of the PGHalpha and FSHbeta in an avian species.

Cloning and gene expression of a cDNA for the chicken follicle-stimulating hormone (FSH)-beta-subunit

Follicle-stimulating hormone (FSH) is a member of pituitary glycoprotein hormones that are composed of two dissimilar subunits, alpha and beta. Very little information is available regarding the nucleotide and amino acid sequence of FSH-beta in avian species. For better understanding of the phylogenic diversity and evolution of FSH molecule, we have isolated and sequenced the complete complementary DNA (cDNA) encoding chicken FSH-beta precursor molecule by reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA end (RACE) methods. The cloned chicken FSH-beta cDNA consists of 2457-bp nucleotides, including 44-bp nucleotides of the 5'-untranslated region (UTR), 396 bp of the open reading frame, and an extraordinarily long 3'-UTR of 2001-bp nucleotides followed by a poly(A)((16)) tail. It encodes a 131-amino-acid precursor molecule of FSH-beta-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 chicken FSH-beta-subunit. Four proline residues, presumably responsible for changing the backbone direction of protein structure, are conserved in chicken FSH-beta-subunit as well. The nucleotide sequence of chicken FSH-beta cDNA shows high homology with quail FSH-beta cDNA, 97% homology in the open reading frame, and 85% homology in the 3'-UTR. The deduced amino acid sequence of chicken FSH-beta-subunit shows a remarkable similarity to other avian FSH-beta-subunits, 98% homology with quail, and 93% homology with ostrich, whereas a lower similarity (66 to 70%) is noted when compared with mammalian FSH-beta-subunits. By contrast, when comparing with the beta-subunits of chicken luteinizing hormone and thyroid-stimulating hormone, the homologies are as low as 37 and 40%, respectively. FSH-beta mRNA was only expressed in pituitary gland out of various tissues examined and can be up-regulated by gonadotropin-releasing hormone in pituitary tissue culture as estimated by real-time quantitative PCR.

Spatio-temporal expression of TSH beta and FSH beta genes in normally metamorphosing, metamorphosed, and metamorphosis-arrested Hynobius retardatus

Expression patterns of TSH beta and FSH beta genes were investigated in normally metamorphosing and metamorphosed individuals and in goitrogen-treated (TU-SPC), metamorphosis-arrested larvae of a Japanese salamander, Hynobius retardatus, a particular population of which had been reported to show neoteny. Cloned sequences for Hynobius TSH beta and FSH beta covered 66 and 56% of full-length genes, respectively, and both showed relatively high similarity to those of other vertebrates. TSH beta-expressing cells were observed at the ventro-caudal region of the pars distalis of controls, whereas an extraordinarily large number of cells which occupied the whole area of the pituitary glands strongly expressed TSH beta in TU-SPCs. In contrast, no FSH beta-expressing cells were observed in the pituitary glands of controls, whereas several positive cells were observed in the pituitary glands of TU-SPCs. Northern blot analyses revealed a rapid increase of TSH beta expression in the pituitary gland of TU-SPCs that finally reached the level of 20- to 30-fold as much as that of controls. Surprisingly, the expression of FSH beta also increased in the pituitary gland of TU-SPCs compared with that of controls. On the other hand, triiodothyronine administration to the control juveniles reduced the expression of TSH beta compared with saline-administrated controls, suggesting that thyroid hormone (TH) exerts a repressing effect on TSH beta gene. These results suggest that TSH beta overexpression in TU-SPCs must be caused by a deprivation of TH which plays a role in the negative feedback system and that FSH beta expression also might be enhanced by mechanisms similar to those of TSH beta, probably due to certain overlapping of the endocrinological regulation of TSH and FSH in H. retardatus.

Cloning of complementary deoxyribonucleic acid for the follicle-stimulating hormone-beta subunit in the Japanese quail

Complementary DNA clones encoding the luteinizing hormone-beta and common alpha subunits have been isolated not only in mammals but also in some nonmammalian tetrapod vertebrates. However, cloning of cDNA encoding the follicle-stimulating hormone (FSH)-beta subunit is limited to mammals, and no clone for the FSH-beta subunit has been isolated for nonmammalian vertebrates. We report here the isolation and characterization of cDNA encoding the FSH-beta subunit precursor molecule in the Japanese quail from a cDNA library of the pituitary gland of this bird. As the hybridization probe for the screening, we used a cDNA clone prepared by the polymerase chain reaction (PCR) with primers designed from known nucleotide sequence data of cDNA for FSH-beta subunit precursors of mammals. The FSH-beta subunit precursor cDNA we isolated was longer than any other FSH-beta subunit precursor cDNAs previously reported. This is due to the extraordinarily long 3'-untranslated region (2135 bp). This region is extremely rich in consensus sequences reported to cause instability of mRNA, suggesting that mRNA for the FSH-beta subunit, especially that of the Japanese quail, is unstable. Northern blot analysis of mRNA for the FSH-beta subunit revealed that the pituitary content of mRNA in the nonbreeding season was about 1/5 to 1/10 that in the breeding season in male Japanese quail kept in an outdoor cage. The profile of the seasonal change in FSH-beta subunit mRNA in the quail pituitary gland was similar to that of the seasonal change in the concentration of FSH in plasma reported previously. The deduced amino acid sequence of the mature protein region showed that the quail FSH-beta subunit is more similar to the opossum FSH-beta subunit than to the other mammalian FSH-beta subunits.