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.
Shen
San-Tai
ST
Endocrinology Laboratory, Institute of Zoology, Academia Sinica, Taipei, 115, Taiwan, Republic of China.
Yu
John Yuh-Lin
JY
D020413:3' Untranslated Regions / Q000235:genetics; D020121:5' Untranslated Regions / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000096:biosynthesis* / Q000235:genetics*; D005640:Follicle Stimulating Hormone / Q000096:biosynthesis* / Q000235:genetics*; D037201:Follicle Stimulating Hormone, beta Subunit; D005786:Gene Expression Regulation / Q000502:physiology*; D007987:Gonadotropin-Releasing Hormone / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D010902:Pituitary Gland / Q000737:chemistry / Q000378:metabolism*; D012313:RNA / Q000096:biosynthesis / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction
D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D018076:DNA, Complementary; D037201:Follicle Stimulating Hormone, beta Subunit; D007987:Gonadotropin-Releasing Hormone; D012313:RNA; D005640:Follicle Stimulating Hormone