Sequence analysis of XXXX parathyroid hormone messenger ribonucleic acid.

@entity35 @entity4727 @entity377 @entity1640
@entity4727 -like peptides and messenger RNA (mRNA) have recently been detected in neural tissues, but it is uncertain whether this reflects the transcription of the @entity4727 gene or that of a closely related gene. This possibility has, therefore, been investigated. @entity4727 -like complementary DNA (cDNA) moieties of predicted size were readily generated from reverse transcribed brain ( @entity1640 and extrahypothalamic tissue) and pituitary RNA, using polymerase chain reaction (PCR) with three sets of overlapping oligonucleotide primers designed to amplify @entity4727 cDNA fragments of 285, 372, and 459 base pairs (bp). PCR reamplification of the largest @entity1640 moiety with an internal set of primers also generated a cDNA fragment of the predicted size (372 bp). Restriction endonuclease digestion with BstNI cleaved the largest @entity1640 cDNA moieties into smaller fragments of 217 and 242 bp, identical to the cleavage of parathyroidal @entity4727 cDNA. Rapid amplification of cDNA ends of the 3'-flanking cDNA sequences also produced @entity1640 and extra- @entity1640 cDNA moieties identical in size (499 bp) to parathyroidal @entity4727 cDNA. Southern analysis of these PCR and rapid amplification of cDNA end cDNA fragments further indicated homology with @entity4727 cDNA. This homology was subsequently confirmed by @entity377 sequencing, which demonstrated complete homology between the neural and parathyroidal cDNA fragments. This homology extended over 673 bp (spanning nucleotides 31-709 of @entity4727 cDNA), encompassing 95% of the entire parathyroidal @entity4727 cDNA. The mRNA for this gene, determined by Northern blotting with a riboprobe for @entity4727 mRNA, was of identical size to the parathyroidal @entity4727 , but its abundance in brain was less than 0.01% of that expressed in the parathyroid glands. This transcript was not, however, detected in liver. The translation of this moiety in @entity1640 tissues was indicated by the presence of a protein in the @entity35 hypothalamus that was immunoreactive with @entity4727 ) antiserum and of comparable size to that in parathyroidal tissue. The abundance of this protein in @entity1640 tissue was approximately 0.25% of that in the parathyroid glands, suggesting tissue-specific differences in its rate of synthesis, processing, or degradation. These results, therefore, demonstrate that the brain is an extraparathyroidal site of @entity4727 gene expression and suggest autocrine or paracrine roles for @entity4727 in neural function.
