Brain Expression Of X-linked Gene Cloning, Chromosomal Localization, And Preliminary Function Study

Through screening a human fetal brain cDNA library, a cDNA similar to the mouse Bexl was isolated. This new gene was named brain expressed X-linked protein 1 (BEX1). Northern blot analysis revealed a 1.0 kb transcript highly expressed at brain, pancreas, testis, and ovary, with lower levels present in heart, placenta, liver, kidney, spleen, thymus, prostate, small intestine, colon (no mucose), thyroid, spinal cord, and adrenal gland. No hybridization signal was seen in lung, skeletal muscle, peripheral blood leukocyte, stomach, lymph node, trachea and bone marrow. The BEX1 gene was localized to chromosome band Xq22 between markers between DXS990 and DXS 1059 by screening Stanford radiation hybrid G3 panels. In situ hybridization of mouse testis using BEX1 as probe, the signal was detected in the pachytene spermatocytes and spermatids but not in spermatogonia. Furthermore, it was not detected at the day 6, day 9, and day 12 postpartum, presented lowly at age of 15, 18 days and its expression was increased sharply after the initiation of puberty (about 21 days) in mouse testis.