Identification and characterisation of alternative splice variants of HOXB9 and their correlation with melanogenesis in the black-boned chicken

Wang, GangYu, ShigangLiao, Juan

Homeobox B9 (HOXB9) gene has been demonstrated to be associated with melanogenesis in chicken plumage by high-throughput RNA sequencing. In this study, we cloned and characterised HOXB9 in black-boned chickens. Two alternative splice variants (HOXB9-1 and HOXB9-2) were identified in chicken feather bulbs. Expression analysis of HOXB9 in 11 different chicken tissues by RT-PCR indicated that the two transcripts were only expressed in the kidney, abdominal fat, feather bulbs, skin, and small intestine. No HOXB9-1 or HOXB9-2 transcripts were detected in the breast muscle or the ovary. The two HOXB9 variants were expressed at significantly different levels in black feather bulbs and white feather bulbs (p<0.01), and in black skin compared with white skin (p<0.01). The results indicate that HOXB9-1 and HOXB9-2 may be involved in melanin formation in the plumage and skin. The expression of HOXB9-2 was higher in white than in black muscles (p<0.05), HOXB9-2 may play a role in muscle melanogenesis. Our results suggest that HOXB9, which is partially regulated by alternative splicing, may be involved in the process of melanogenesis in the black-boned chicken.(AU)

1. Homeobox B9 gene
2. Melanin
3. Alternative splicing variant
4. Chicken