Expression of connexin 43 mRNA in porcine and equine ovaries

A major form of cell-cell communication is mediated by gap junctions, aggregations of intercellular channels responsible for the exchange of cytosolic materials (<1 kD) between adjacent cells. These channels are composed of connexins, a steadily growing family of highly related proteins. Several studies have suggested that connexin channels between granulosa cells and oocytes maintain meiotic arrest in growing follicles and mediate release of this arrest after the gonadotropin surge. Most major livestock species such as cattle, sheep, and pigs have been examined for the presence of gap junctions; however, extensive studies of ovarian gap junctions have been conducted mainly in the rodent, fish, and Xenopus species. Previously, a cDNA clone was isolated from ovaries of cyclic gilts and sequence analysis demonstrated that the fragment had 94.2% amino acid identity with mouse connexin 43. In order to determine the spatio-temporal pattern of expression for connexin 43 mRNA in porcine and equine ovaries, a 412 base fragment of the cDNA was used to synthesize probes for Northern and in situ hybridization studies.