TY - JOUR
T1 - Identification and localisation of T-type voltage operated calcium channel subunits in human male germ cells - expression of multiple isoforms
AU - Jagannathan, Suchitra
AU - Punt, Emma
AU - Gu, Yuchun
AU - Arnoult, C
AU - Sakkas, Dionisios
AU - Barratt, Christopher
AU - Publicover, Stephen
PY - 2002/3/1
Y1 - 2002/3/1
N2 - Low voltage activated, voltage-operated Ca2+ channels are expressed in rodent male germ cells and are believed to be pivotal in induction of the acrosome reaction in mouse spermatozoa. However, in humans, very little is known about expression of voltage-operated Ca2+ channels in male germ cells or their function. We have used reverse transcription-polymerase chain reaction, in situ hybridization, and patch clamp recording to investigate the expression of low voltage activated voltage-operated Ca2+ channels in human male germ cells. We report that full-length transcripts for both alpha(1G) and alpha(1H) low voltage activated channel subunits are expressed in human testis. Multiple isoforms Of alpha(1G) are present in the testis and at least two isoforms of alpha(1H), including a splice variant not previously described in the human. Transcripts for all the isoforms of both alpha(1G) and alpha(1H) were detected by reverse transcription-polymerase chain reaction on mRNA isolated from human spermatogenic cells. In situ hybridization for alpha(1G) and all, localized transcripts both in germ cells and in other cell types in the testis. Within the seminiferous tubules, alpha(1H) was detected primarily in germ cells. Using the whole cell patch clamp technique, we detected T-type voltage-operated Ca2+ channel currents in isolated human male germ cells, although the current amplitude and frequency of occurrence were low in comparison to the occurrence of T-currents in murine male germ cells. We conclude that low voltage activated voltage-operated Ca2+ channels are expressed in cells of the human male germ line.
AB - Low voltage activated, voltage-operated Ca2+ channels are expressed in rodent male germ cells and are believed to be pivotal in induction of the acrosome reaction in mouse spermatozoa. However, in humans, very little is known about expression of voltage-operated Ca2+ channels in male germ cells or their function. We have used reverse transcription-polymerase chain reaction, in situ hybridization, and patch clamp recording to investigate the expression of low voltage activated voltage-operated Ca2+ channels in human male germ cells. We report that full-length transcripts for both alpha(1G) and alpha(1H) low voltage activated channel subunits are expressed in human testis. Multiple isoforms Of alpha(1G) are present in the testis and at least two isoforms of alpha(1H), including a splice variant not previously described in the human. Transcripts for all the isoforms of both alpha(1G) and alpha(1H) were detected by reverse transcription-polymerase chain reaction on mRNA isolated from human spermatogenic cells. In situ hybridization for alpha(1G) and all, localized transcripts both in germ cells and in other cell types in the testis. Within the seminiferous tubules, alpha(1H) was detected primarily in germ cells. Using the whole cell patch clamp technique, we detected T-type voltage-operated Ca2+ channel currents in isolated human male germ cells, although the current amplitude and frequency of occurrence were low in comparison to the occurrence of T-currents in murine male germ cells. We conclude that low voltage activated voltage-operated Ca2+ channels are expressed in cells of the human male germ line.
UR - http://www.scopus.com/inward/record.url?scp=0037040909&partnerID=8YFLogxK
U2 - 10.1074/jbc.M105345200
DO - 10.1074/jbc.M105345200
M3 - Article
C2 - 11751928
SN - 1083-351X
VL - 277
SP - 8449
EP - 8456
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 10
ER -