First evidence of prothymosin alpha in a non-mammalian vertebrate and its involvement in the spermatogenesis of the frog Rana esculenta.
A cDNA clone encoding for a Prothymosin alpha (Prot-alpha) has been isolated and characterized from the testis of the frog Rana esculenta. Frog Prothymosin alpha (fProt-alpha) predicted a 109 amino acid protein with a high homology to the mammalian Prot-alpha. fProt-alpha contains 28 aspartic and 25 glutamic acid residues and presents the typical basic KKQK amino acid sequence in the close carboxyl terminal region. Northern blot analysis revealed that fProt-alpha is highly expressed in the testis. A different expression of fProt-alpha transcript was found during the frog reproductive cycle with a peak in September/October in concomitance with germ cell maturation, strongly suggesting a role for this protein in the testicular activity. In situ hybridization evidenced that the only germ cells expressing fProt-alpha are the primary and secondary spermatocytes; in addition, the hybridization signal was stronger in the October testis. Taken together, our findings indicate that fProt-alpha might contribute to the efficiency of frog spermatogenesis with a role during the meiosis. This study is the first report on the isolation and characterization of a Prot-alpha in a non-mammalian vertebrate. In addition, our results indicate that the testis of the frog R. esculenta may be a useful model to increase the knowledge concerning the physiological role of Prot-alpha in vertebrates.
Aniello
Francesco
F
Dipartimento di Genetica, Biologia Generale e Molecolare Università degli Studi di Napoli Federico II - Via Mezzocannone 8, 80138 Naples, Italy.
Branno
Margherita
M
De Rienzo
Gianluca
G
Ferrara
Diana
D
Palmiero
Carmela
C
Minucci
Sergio
S
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D011498:Protein Precursors / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011893:Rana esculenta / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D013091:Spermatogenesis / Q000235:genetics / Q000502:physiology*; D013947:Thymosin / Q000031:analogs & derivatives* / Q000235:genetics / Q000502:physiology*
D018076:DNA, Complementary; D011498:Protein Precursors; D012333:RNA, Messenger; C040782:prothymosin alpha; D013947:Thymosin