Latar Belakang: Beberapa gen yang terekspresi spesfik di epididimis diduga

terlibat dalam proses pematangan sperma. Karakteristik gen yang terlibat dalampematangan sperma selain ekspresinya spesifik di epididimis juga dipengaruhioleh androgen, faktor testikuler, dan terekspresi pada saat masa pubertas. Salahsatu famili gen yang cukup banyak ditemukan terekspresi di epididimis adalahBeta Defensin. Gen Beta Defensin diketahui memiliki peran sebagai pertahananterhadap mikroba, namun diduga memiliki keterlibatan dalam proses pematangansperma karena ekspresinya banyak ditemukan di epididimis. Oleh karena itu,penelitian pada gen Beta Defensin terhadap perannya dalam proses pematangansperma perlu dilakukan. Berdasarkan studi sebelumnya diketahui bahwa salahsatu gen Beta Defensin yang terekspresi di epididimis yaitu Beta Defensin 2(Defb2), namun karakterisasi terhadap gen ini belum dilakukan. Dengandemikian, pada penelitian ini bertujuan untuk mengkarakterisasi gen Defb2 terkaitdengan perannya pada proses pematangan sperma.Metode: Analisis bioinformatika digunakan untuk mendapatkan informasi

mengenai struktur gen, signal peptide, dan domain fungsional pada gen Defb2.

Analisis qRT-PCR untuk mengetahui ekspresi relatif gen Defb2 pada berbagai

jaringan, regulasinya oleh androgen, pengaruh dari faktor testikular dan

ekspresinya pada perkembangan postnatal.Hasil: Defb2 merupakan protein sekretori karena memiliki signal peptide. Defb2

memiliki domain fungsional berupa N-myristoylation dan protein kinase-C. Gen

Defb2 terekspresi spesifik di epididimis khususnya pada bagian caput epididimis.

Defb2 ekspresinya dipengaruhi oleh androgen terbukti setelah perlakuan

gonadektomi, ekspresi Defb2 menjadi menurun dan kembali mengalami kenaikan

ketika diberikan testosteron eksogen. Defb2 juga ekspresinya dipengaruhi oleh

faktor testikuler terbukti setelah diberi perlakuan Efferent Duct Ligation (EDL)

maka ekspresi Defb2 langsung menurun bahkan terjadi apoptosis sel sehingga

pola ekspresi gen Defb2 sudah tidak bisa diamati. Begitu juga pada analisis

postnatal development terlihat ekspresi gen Defb2 mulai terdeteksi jelas pada hari

ke-15 yang merupakan masa pubertas mencit jantan.Kesimpulan: Defb2 merupakan gen yang terlibat dalam proses pematangan

sperma di epididimis yang dibuktikan dengan ekspresi spesifik di epididimis,

diregulasi oleh androgen dan faktor testikuler, serta mulai terekspresi pada masa

pubertas.

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Background: Some of the specific genes expression in the epididymis are

suspected to be involved in the process of sperm maturation. Characteristics of thegenes involved in sperm maturation in the epididymis-specific expression inaddition also influenced by androgens, testicular factors, and expressed at the timeof puberty. One of a family of genes that is pretty much found expressed in theepididymis is a Beta Defensins. Beta Defensin genes known to have a role as adefence against microbes, but suspected to have involvement in the process ofsperm maturation because the expression is found in the epididymis. Therefore,research on Beta Defensin genes against its role in sperm maturation processneeds to be done. Based on previous studies it is known that one of the BetaDefensin genes which expressed in the epididymis that is Beta Defensins 2(Defb2), but the characterization of this gene has not been made against. Thus,this research aims to characterize genes associated with the Defb2 role in theprocess of sperm maturation.Methods: Bioinformatics analysis was used to obtain information about the

structure of genes, signal peptides, and functional domains of the Defb2 gene.

qRT-PCR analysis to find out the relative gene expression of Defb2 on various

tissue, regulation by androgens, the effect of testicular factors and its expression

in postnatal development.Results: Defb2 is a secreted protein because it has signal peptides. Defb2 has a

functional domain in the form of N-myristoylation and kinase-C protein. Specific

genes expression of Defb2 in the epididymis is especially in the caput epididymis.

Defb2 expression influenced by androgens is proven after the gonadectomy, the

expression of Defb2 to be decreased and start increase again when exogenous

testosterone is given. Defb2 also its expression influenced by testicular factors

that proven after being given the treatment by Efferent Duct Ligation (EDL), then

the Defb2 expressions directly decreased and the cell apoptosis occurs even so

that the pattern of gene expression Defb2 already could not be observed. So also

on analysis of postnatal development seen gene expression Defb2 begins to be

detected clearly at day 15 which is a male mice puberty.Conclusions: Defb2 is a gene which is involved in the process of maturation of

sperm in the epididymis that is evidenced by specific expression in the

epididymis, be regulated by androgens and testicular factors, and as well as start

expressed at puberty.