Expression of the putative sterol binding protein Stard6 gene is male germ cell specific.
Mammalian spermatogenesis is orchestrated by many specific molecular and cellular events. To understand the detailed mechanism by which spermatogenesis is controlled, the specific genes involved in this process must be identified and studied. From the subtracted cDNA library of rat testis prepared using the representational difference analysis (RDA) method, we isolated the cDNA clone of steroidogenic acute regulatory (StAR) protein-related lipid transfer (START) protein 6 (Stard6). Stard6 cDNA consists of 1146 base pairs of nucleotides and has the longest open reading frame, of 227 amino acids. Northern blot analysis revealed Stard6 mRNA to be testis-specific. The mRNA transcript appeared from the third week of postnatal development, and the expression level increased up to adulthood. Moreover, in situ hybridization showed Stard6 mRNA expression to be germ cell-specific and expressed only during the maturation stages of round and elongated spermatids of adult rat testis. Western blot analysis with Stard6 antibody revealed a 28-kDa Stard6 protein only in testis. Immunohistochemistry further confirmed localization of Stard6 protein expressed in mature germ cells, in concert with the in situ hybridization result. Taken together, these results suggest that Stard6, a member of the START protein family, may play a role during germ cell maturation in adult rat testis.
Gomes
Cynthia
C
Hormone Research Center, Department of Molecular Endocrinology, School of Biological Sciences and Technology, Chonnam National University, Gwangju 500-757, Republic of Korea.
Oh
Sung-Dug
SD
Kim
Jung-Woo
JW
Chun
Sang-Young
SY
Lee
Keesook
K
Kwon
Hyuk-Bang
HB
Soh
Jaemog
J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000502:physiology; D018076:DNA, Complementary / Q000032:analysis; D018507:Gene Expression Regulation, Developmental; D005854:Germ Cells / Q000378:metabolism*; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017385:Sequence Homology; D012727:Sex Characteristics; D013091:Spermatogenesis / Q000502:physiology*; D013737:Testis / Q000166:cytology / Q000378:metabolism*
D018076:DNA, Complementary; D026901:Membrane Transport Proteins; D012333:RNA, Messenger; C456545:STARD6 protein, human