A novel poly(A)-binding protein gene (PABPC5) maps to an X-specific subinterval in the Xq21.3/Yp11.2 homology block of the human sex chromosomes

The gene-poor human-specific Xq21.3/Yp11.2 block of homology exhibits 99% n ucleotide identity, with the exception of an internal X-specific region con taining the marker DXS214. This paper describes the characterization of a n ovel gene (PABPC5) from this X-specific subinterval that belongs to the pol y(A)-binding protein gene family. The genomic structure of PABPC5 covers 40 61 bp of an uninterrupted open reading frame (ORF) and a 5'UTR spanning acr oss two exons and associated with a CpG island; the potential 382-amino-aci d protein contains four RNA recognition motif domains, PABPC5 has 73% nucle otide identity with PABPC4 over 1801 bp of the ORF, At the protein level, 6 0% identity and 75% similarity are obtained in the comparison with human. P ABPC4, as well as human, mouse, and Xenopus PABPC1. RT-PCR indicates that P ABPC5 is expressed in fetal brain and in a range of adult tissues. Conserva tion of the PABPC5 ORF and genomic structure is shown in primates and roden ts. The close proximity of this gene to translocation breakpoints associate d with premature ovarian failure makes it a potential candidate for this co ndition. (C) 2001 Academic Press.