Novel alternatively spliced mRNA (1c) of the protein kinase A RI&alpha; subunit is implicated in haploid germ cell specific expression.
By using 5' RACE on rat testis cDNA we identified three alternatively spliced mRNAs of the RIalpha subunit of cAMP-dependent protein kinase that differed in their 5' untranslated regions. Two of these 5'-regions showed similarity with the human RIalpha exons 1a and 1b, while the third (1c) constituted a novel mRNA splice variant. Northern blot analysis showed that the 1c mRNA was specifically expressed in testis and only in postmeiotic germ cells. In contrast, the RIalpha 1b and RIalpha 1a mRNAs were present both in premeiotic germ cells and somatic cells of the testis, and the expression of both RIalpha 1a and 1b mRNAs were stimulated by cAMP in Sertoli cells. In sperm, the RIalpha protein was expressed after meiosis, and targeted to various subcellular structures via anchoring proteins. The RIalpha 1c haploid-specific mRNA, therefore, may be important for the regulation of RIalpha expression in sperm.
Dahle
M K
MK
Institute of Medical Biochemistry, University of Oslo, Oslo, Norway. maria.krudtaa@basalmed.uio.no
Reinton
N
N
Orstavik
S
S
Taskén
K A
KA
Taskén
K
K
D020121:5' Untranslated Regions / Q000235:genetics*; D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002458:Cell Fractionation; D003001:Cloning, Molecular; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D021122:Protein Subunits; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism*; D013737:Testis / Q000166:cytology / Q000502:physiology
D020121:5' Untranslated Regions; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; C517834:PRKAR1A protein, human; C517836:Prkar1a protein, rat; D021122:Protein Subunits; D012333:RNA, Messenger; D017868:Cyclic AMP-Dependent Protein Kinases